Magnetoelectric conversion element

Abstract

To provide a magnetoelectric conversion element capable of ensuring independence of vibration of each vibrating body.SOLUTION: A magnetoelectric conversion element includes: a substrate in which a plurality of lower spaces with at least part of a fixed part arranged therebetween is formed; and a plurality of vibrating bodies which is provided corresponding to the lower spaces and each of which is supported to be vibratable on the lower space via a support arm part connected to the fixed part, the vibrating bodies having magnetoelectric conversion properties. Each lower space is connected to an upper space, which is an upper space of the vibrating body, via a gap between the corresponding vibrating body and the substrate. The cross sectional area of a first cross section that is parallel to a main surface of the vibrating body in the fixed part and has a first distance from the upper end of the fixed part is narrower than the cross sectional area of a second cross section that is parallel to the main surface of the vibrating body in the fixed part and has a second distance from the upper end of the fixed part, the second distance being longer than the first distance.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a magnetoelectric transducer having a plurality of vibrating bodies. [Background technology]

[0002] A technique for constructing a magnetoelectric transducer by combining a piezoelectric material with a ferromagnetic material has been proposed, and the development of various devices using the magnetoelectric transducer is being considered. For example, a magnetoelectric transducer having a vibrating body with magnetoelectric properties arranged on a substrate has been proposed as a small and useful magnetoelectric transducer.

[0003] On the other hand, if an energy conversion element could be constructed by combining multiple small energy conversion parts, it would be possible to realize a small yet high-performance energy conversion element. However, if multiple vibrating bodies with magnetoelectric conversion properties are densely arranged on a substrate, the substrate supporting the vibrating bodies will vibrate, resulting in a problem of reduced magnetoelectric conversion properties. Furthermore, if multiple vibrating bodies are arranged close together, the vibrations between them will be transmitted, resulting in a problem of reduced magnetoelectric conversion properties and difficulty in control. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-169881 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in view of the above circumstances, and provides a magnetoelectric transducer having a plurality of vibrating bodies, which can ensure the independence of vibration of each vibrating body. [Means for solving the problem]

[0006] In order to achieve the above object, a magnetoelectric transducer according to the present invention comprises: a substrate having a plurality of lower spaces formed therein, between which at least a portion of the fixing portion is disposed; a plurality of vibrating bodies provided corresponding to the lower space, supported in a vibratory manner on the lower space via support arms connected to the fixed portion, and having magnetoelectric transduction properties; Each of the lower spaces is connected to an upper space, which is a space above the corresponding vibrating body, via a gap between the vibrating body and the substrate, The cross-sectional area of ​​a first cross section parallel to the main surface of the vibrating body in the fixed portion and a first distance from the upper end of the fixed portion is narrower than the cross-sectional area of ​​a second cross section parallel to the main surface of the vibrating body in the fixed portion and a second distance from the upper end of the fixed portion that is longer than the first distance.

[0007] In the magnetoelectric transducer according to the present invention, by arranging the vibrating bodies so that at least a portion of the fixed part corresponds to the lower space between them, it is possible to arrange multiple vibrating bodies close to each other. Furthermore, by narrowing the cross-sectional area of ​​the first cross section of the fixed part, multiple vibrating bodies can be arranged closer to each other while ensuring space for the vibrating bodies and the support arms to be arranged and vibrate. Furthermore, by widening the second cross section, the rigidity of the fixed part is increased, preventing the fixed part from vibrating, ensuring the independence of the vibration of each vibrating body, and achieving good magnetoelectric conversion characteristics.

[0008] Furthermore, for example, the primary resonance frequency of the fixed portion may be lower than the resonance frequency at which the vibrating body operates.

[0009] Such a magnetoelectric conversion element can effectively prevent vibration of the fixed part that supports the vibrating body by preventing resonance of the fixed part caused by the movement of the vibrating body, thereby achieving good magnetoelectric conversion characteristics.

[0010] Furthermore, for example, the fundamental resonance frequency of a vibration mode of the fixed portion displaced in the same direction as the vibration direction of the vibration mode in which the vibrating body operates may be lower than the resonance frequency in which the vibrating body operates.

[0011] Such a magnetoelectric conversion element can particularly effectively prevent vibration of the fixed part that supports the vibrating body by preventing resonance of the fixed part caused by the movement of the vibrating body, thereby obtaining good magnetoelectric conversion characteristics.

[0012] Furthermore, for example, the fixed portion may have a transition change portion in which the cross-sectional area of ​​a cross section of the fixed portion parallel to the main surface of the vibrating body gradually narrows as the distance from the upper end of the fixed portion decreases.

[0013] The fixing portion having the transition change portion can prevent the cross-sectional area of ​​the fixing portion from changing suddenly in the vertical direction, and can effectively increase the rigidity of the fixing portion overall.

[0014] Furthermore, for example, the fixing portion may have a step surface connecting a first side surface of a first portion including the first cross section and a second side surface of a second portion including the second cross section.

[0015] By forming the substrate in a shape having such a stepped surface, a fixing portion having a first cross section and a second cross section can be formed relatively easily by etching or the like, and therefore a substrate having such a fixing portion has good productivity.

[0016] The vibrating body may have a film stack including a piezoelectric film and a ferromagnetic film.

[0017] A vibrating body having a film laminated portion including a piezoelectric film and a ferromagnetic film is small and exhibits good magnetoelectric conversion properties. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a partial plan view of a magnetoelectric transducer element according to one embodiment of the present invention. [Figure 2]FIG. 2 is an enlarged plan view of the periphery of one vibrator included in the magnetoelectric transducer shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV shown in FIG. [Figure 5] FIG. 5 is a conceptual diagram that schematically shows the shapes of the fixed portion and vibrating body in the magnetoelectric transducer. [Figure 6] FIG. 6 is a conceptual diagram that schematically shows the shapes of the fixed portion and the vibrating body in the magnetoelectric transducer according to the second embodiment. [Figure 7] FIG. 7 is a conceptual diagram that schematically shows the shapes of the fixed portion and the vibrating body in the magnetoelectric transducer according to the third embodiment. [Figure 8] FIG. 8 is a conceptual diagram that schematically shows the shapes of the fixed portion and the vibrating body in the magnetoelectric transducer according to the fourth embodiment. [Figure 9] FIG. 9 is a conceptual diagram that schematically shows the shapes of the fixed portion and the vibrating body in the magnetoelectric transducer according to the fifth embodiment. [Figure 10] FIG. 10 is a conceptual diagram that schematically shows the shapes of the fixed portion and the vibrating body in the magnetoelectric transducer according to the sixth embodiment. [Figure 11] FIG. 11 is a conceptual diagram that schematically shows the shapes of the fixed portion and the vibrating body in the magnetoelectric transducer according to the seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention will be described in detail below based on the embodiments shown in the drawings.

[0020] First embodiment Fig. 1 is a partial plan view of a magnetoelectric transducer 30 according to a first embodiment of the present invention. As shown in Fig. 1, the magnetoelectric transducer 30 has a substrate 40 in which a plurality of lower spaces 40b are formed with fixed portions 41 disposed therebetween, and a plurality of vibrating bodies 70 having magnetoelectric transduction properties and provided corresponding to each lower space 40b. For convenience of explanation, the cover portion 90 shown in Fig. 5(b) is omitted from Figs. 1 to 4 and 5(a).

[0021] 1, the substrate 40 has a plurality of lower spaces 40b formed along the X-axis and Y-axis directions, each having a substantially rectangular upper opening when viewed from above (positive direction of the Z-axis). Each lower space 40b is separated in the X-axis direction by a fixing portion 41, and separated in the Y-axis direction by a connecting portion 48. A frame portion 49 (see FIG. 5(b)) of the substrate 40 forms the outer periphery of the substrate 40.

[0022] The vibrating body 70 is disposed so as to cover a portion of the upper opening of each lower space 40b. Fig. 2 is an enlarged plan view showing one of the vibrating bodies 70 shown in Fig. 1 and its surrounding area, and Figs. 3 and 4 are cross-sectional views taken along the cross-sectional lines III-III and IV-IV in Fig. 2, respectively. Note that Figs. 2 to 4 also show the detailed structure of the vibrating body 70, which is not shown in Fig. 1.

[0023] 2 and 3, the vibrating body 70 is supported so as to be able to vibrate above the lower space 40b via support arm parts 80 connected to the fixed parts 41. As shown in Fig. 2 and 4, gaps 94 are formed between the vibrating body 70 and the fixed parts 41 and connecting parts 48 of the substrate 40. As shown in Fig. 4, each lower space 40b is connected to an upper space 90a, which is the space above the vibrating body 70 (on the positive Z-axis direction side), via gaps 94 between the vibrating body 70 and the substrate 40, which is provided corresponding to that lower space 40b.

[0024] As shown in FIG. 1, the magnetoelectric transducer 30 constitutes an array element that electrically connects a plurality of vibrating bodies 70 via electrode films (first extraction electrode film 50a and second extraction electrode film 50b, which will be described later) and wiring portions 96. The magnetoelectric transducer 30 shown in FIG. 1 is a 2D array element in which a plurality of vibrating bodies 70 are arranged in a two-dimensional direction, but the magnetic transducer is not limited to a 2D array element and may be a 1D array element in which a plurality of vibrating bodies 70 are arranged in a one-dimensional direction (for example, the X-axis direction), or a 3D array element in which a plurality of vibrating bodies 70 are arranged three-dimensionally. A magnetic transducer that is a 3D array element can be formed, for example, by stacking a plurality of magnetoelectric transducer elements 30 shown in FIG. 1 in the vertical direction (the Z-axis direction).

[0025] As shown in Fig. 3, which will be described later, the vibrating body 70 of the magnetoelectric transducer 30 includes a piezoelectric film central portion 72 and a ferromagnetic film 73, and has magnetoelectric converting properties for converting magnetic energy to electric energy. The magnetoelectric transducer shown in Fig. 1 can effectively absorb input energy accompanied by fluctuations in an electromagnetic field, for example, to perform magnetoelectric conversion, thereby obtaining a high electric output. Furthermore, the magnetoelectric transducer can efficiently convert, for example, electric input energy into an output signal such as a magnetic field fluctuation.

[0026] The magnetoelectric conversion element 30 is connected to a power source and an electric / electronic circuit, and is mounted on a circuit board or packaged to form an electronic device such as an energy conversion device, a magnetic sensor, etc. Application examples of the magnetoelectric conversion element 30 include, but are not limited to, a small, highly sensitive magnetic sensor that detects magnetism, a highly sensitive magnetic antenna, and a power transmitting unit or a power receiving unit of a contactless power supply system in a small device.

[0027] 1 to 5, the description will be made assuming that the direction connecting the two support arms 80 on both sides of the vibrating body 70 is the X-axis direction, the normal direction of the lower space 40b of the substrate 40 and the main surface 70a of the vibrating body 70 (see FIG. 5(b)) is the Z-axis direction, and the direction perpendicular to the X-axis and Z-axis directions is the Y-axis direction. However, in the magnetoelectric conversion element 30, the X-axis and Y-axis directions do not need to coincide with the horizontal direction, and the element may be arranged so that the Z-axis direction coincides with the horizontal direction, or so that the Z-axis direction is oblique to the horizontal plane.

[0028] 2, the combined portion of one vibrating body 70 and the lower space 40b in the magnetoelectric transducer 30 is arranged in a region having a generally rectangular shape in plan view as a whole. The vibrating body 70 is formed along a plane including the X-axis and the Y-axis, and has a generally rectangular shape in plan view.

[0029] Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2. As shown in Fig. 3, the substrate 40 is present at the bottommost layer in the Z-axis direction of the magnetoelectric transducer 30. The substrate 40 has a lower space 40b in a portion that overlaps with the vibrating body 70 when viewed from the Z-axis direction. The vibrating body 70, which is located above the lower space 40b in the Z-axis direction, has a film stack portion including a lower metal film central portion 74, a piezoelectric film central portion 72 located above the lower metal film central portion 74, and a ferromagnetic film 73 located above the piezoelectric film central portion 72.

[0030] The film stack portion of the vibrating body 70 is stacked in a state in which a piezoelectric film central portion 72 is sandwiched between a lower metal film central portion 74 and a ferromagnetic film 73. Therefore, a voltage can be applied to the piezoelectric film central portion 72 via the lower metal film central portion 74 and the ferromagnetic film 73. Alternatively, a charge generated in the piezoelectric film central portion 72 can be extracted via the lower metal film central portion 74 and the ferromagnetic film 73.

[0031] Furthermore, in the vibrating body 70, the ferromagnetic film 73 can deform and vibrate in response to the influence of an external magnetic field, etc., and the piezoelectric film central portion 72 also deforms and vibrates together with the ferromagnetic film 73, generating electric charge, which can be extracted via the lower metal film central portion 74 and the ferromagnetic film 73. Furthermore, in the vibrating body 70, a voltage is applied to the piezoelectric film central portion 72 to cause deformation and vibration, which in turn causes the ferromagnetic film 73 to deform and vibrate together with the piezoelectric film central portion 72, thereby generating magnetic field fluctuations. In this way, the vibrating body 70 has magnetoelectric conversion properties.

[0032] As shown in Fig. 3, the support arm 80 is connected to both ends of the vibrating body 70 in the X-axis direction. One end of the support arm 80 is connected to the vibrating body 70, and the other end of the support arm 80 is fixed to the upper end 41a of the fixed part 41. In this way, the support arm 80 connects the vibrating body 70 to the fixed part 41a of the substrate 40 so that the vibrating body 70 can vibrate. As shown in Fig. 3, the support arm 80 includes a lower metal film end part 84 and a piezoelectric film end part 82.

[0033] As shown in Fig. 3, the lower metal film integrally includes a lower metal film central portion 74 of the vibrating body 70 and a lower metal film end portion 84 that is a part of the support arm portion 80. In the plan view shown in Fig. 2, the lower metal film central portion 74 has a substantially rectangular shape that is smaller than the upper opening of the lower space 40b. Therefore, a gap 94 (see Figs. 2 and 4) is formed between the lower metal film central portion 74 and the upper opening of the lower space 40b.

[0034] 3, lower metal film end portions 84 of the lower metal film are located at both ends in the X-axis direction of lower metal film central portion 74, and have a generally rectangular shape with a width in the Y-axis direction smaller than that of central portion 50b in the plan view shown in FIG. 2. Because the lower metal film has the above-described shape, it exists so as to span the upper opening of lower space 40b in the X-axis direction in the cross section shown in FIG. 3. Furthermore, a portion of lower metal film end portion 84 of the lower metal film is connected to and fixed to upper end 41a of fixing portion 41 of substrate 40.

[0035] 4 is a cross-sectional view taken along line IV-IV in FIG. 2. In FIG. 4, only the cross section of the lower metal film central portion 74 is shown, and the lower metal film end portion 84 connected to the fixed portion of the substrate 40 is not shown. Therefore, in the cross section shown in FIG. 4, the vibrating body 70 including the lower metal film central portion 74 appears to be floating above the Z axis of the lower space 40b. The vibrating body 70 disposed above the lower space 40b may warp due to an imbalance in stress among the films included in the vibrating body 702, but a small warp is preferable from the viewpoint of reducing energy transmission loss within the magneto-electric conversion element 30.

[0036] As shown in Fig. 3, the piezoelectric film central portion 72 is located above the lower metal film central portion 74 in the Z-axis direction and has a substantially rectangular shape in plan view that is the same as or slightly smaller than the lower metal film central portion 74. In Fig. 2, the planar dimensions (area on the XY plane) of the piezoelectric film central portion 72 are smaller than the planar dimensions of the lower metal film central portion 74, but the planar dimensions of the piezoelectric film central portion 72 may be approximately the same as those of the lower metal film central portion 74. As shown in Fig. 3, in addition to the piezoelectric film central portion 72, the piezoelectric film has piezoelectric film end portions 82 that are connected to both ends of the piezoelectric film central portion 72 and are located above the lower metal film end portions 84. The piezoelectric film end portions 82, like the lower metal film end portions 84, constitute part of the support arm portion 80.

[0037] 3, a ferromagnetic film 73 is present above the piezoelectric film central portion 72 in the Z-axis direction, and as shown in FIG. 2, this ferromagnetic film 73 also has a substantially rectangular shape in plan view. The planar dimensions of the ferromagnetic film 73 are slightly smaller than the planar dimensions of the piezoelectric film central portion 72. Making the planar dimensions of the ferromagnetic film 73 smaller than those of the piezoelectric film central portion 72 tends to improve the durability of the magneto-electric transducer 30. However, the planar dimensions of the ferromagnetic film 73 may be approximately the same as the planar dimensions of the piezoelectric film central portion 72.

[0038] 3, the tip of the first extraction electrode film 51 is connected to one (X-axis negative direction side) lower metal film end 84. The rear end of this first extraction electrode film 51 is connected to the second extraction electrode film 53, which is connected to the ferromagnetic film 73 of the adjacent vibrating body 70 on the X-axis negative direction side, and so on, thereby forming an array element as shown in FIG.

[0039] 3, the other (X-axis positive direction) lower metal film end 84 is covered with an insulating film 54, along with part of the piezoelectric film. A second extraction electrode film 53 is formed spanning the insulating film 54 in the X-axis direction, and the tip of the second extraction electrode film 53 is connected to the ferromagnetic film 73. The rear end of this second extraction electrode film 53 is connected to the first extraction electrode film 51, which is connected to the lower metal film end 83 of the adjacent vibrating body 70 on the X-axis positive direction side, thereby forming an array element as shown in FIG. 1. Note that, due to the presence of the insulating film 54, the second extraction electrode film 53 is insulated from the lower metal film 50 shown in FIGS. 3 and 2.

[0040] As shown in Fig. 1, the plurality of lower spaces 40b formed in the substrate 40 are divided in the X-axis direction by fixing portions 41. Figs. 5(a) and 5(b) are enlarged schematic diagrams showing the peripheral portion of a row of vibrating bodies 70 aligned in the X-axis direction in the magnetoelectric transducer 30 shown in Fig. 1. Fig. 5(a) is a plan view seen from the Z-axis positive direction, and Fig. 5(b) is a cross-sectional view taken along a cross section parallel to the XZ plane. Note that Figs. 5(a) and 5(b) show the shapes of the vibrating bodies 70 and the like in a simplified manner compared to Figs. 2 to 4.

[0041] 5(a), a support arm 80 connected to the adjacent vibrating body 70 on the negative X-axis direction side and a support arm 80 connected to the adjacent vibrating body 70 on the positive X-axis direction side are fixed to the upper end 41a of the fixed portion 41 on the substrate 40. As a result, the fixed portion 41 supports the vibrating body 70 via the support arm 80 so that the vibrating body 70 can vibrate.

[0042] As shown in Fig. 5(b), the fixed portion 41 has a substantially trapezoidal shape in a cross section (longitudinal cross section) perpendicular to the main surface 70a of the vibrating body 70 and parallel to the X-axis direction. Fig. 5(c) is an enlarged view of the cross-sectional shape of the fixed portion 41 shown in Fig. 5(b).

[0043] As shown in Figure 5(c), in the fixed portion 41, the cross-sectional area of ​​a first cross section 42 that is parallel to the main surface 70a (parallel to the XY plane) of the vibrating body 70 and is a first distance L from the upper end 41a of the fixed portion 41 is narrower than that of a second cross section 43 that is parallel to the main surface 70a of the vibrating body 70 and is a second distance L2 that is longer than the first distance L1 from the upper end 41a of the fixed portion 41.

[0044] That is, the fixed portion 41 has a transition change portion in which the cross-sectional area of ​​a cross section parallel to the main surface 70a of the vibrating body 70 gradually narrows as the distance from the upper end 41a of the fixed portion 41 decreases. As shown in Figures 5(b) and 5(c), the entire fixed portion 41 is a transition change portion, and the cross section of the fixed portion 41 has a trapezoidal shape. However, the transition change portion in which the cross-sectional area narrows as the distance from the upper end 41a decreases may be formed only in a part of the fixed portion 41 in the height direction.

[0045] The angle of inclination of the side surface 41b of the fixed portion 41 with respect to the Z-axis direction is not particularly limited, but is preferably 1 to 15 degrees, and particularly preferably 3 to 10 degrees. By shaping the fixed portion 41 in this way, it is possible to arrange the multiple vibrating bodies 70 close to each other, increase the rigidity of the fixed portion 41 to prevent vibration of the fixed portion 41, and ensure the independence of vibration of each vibrating body 70. Note that part of the frame portion 49 of the substrate 40 shown in FIG. 5, where the supporting arm portion 80 is connected, may also be considered to be a type of fixed portion 41.

[0046] (Piezoelectric film) The piezoelectric film having the piezoelectric film center portion 72 and the piezoelectric film end portions 82 is made of a piezoelectric material and exhibits a piezoelectric effect or an inverse piezoelectric effect. The piezoelectric effect refers to the effect of generating an electric charge when an external force (stress) is applied, and the inverse piezoelectric effect refers to the effect of generating strain when a voltage is applied. Examples of piezoelectric materials that exhibit such effects include quartz, lithium niobate, aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT: Pb(Zr,Ti)O3), potassium sodium niobate (KNN: (K,Na)NbO3), and barium calcium zirconate titanate (BCZT: (Ba,Ca)(Zr,Ti)O3).

[0047] In this embodiment, among the above piezoelectric materials, it is particularly preferable to use piezoelectric materials having a perovskite structure, such as PZT, KNN, and BCZT. By using a piezoelectric material with a perovskite structure as the piezoelectric film, it is possible to obtain both excellent piezoelectric properties and high reliability. Note that other elements may be added to the above piezoelectric materials constituting the piezoelectric film 10 as appropriate to improve the properties.

[0048] The thickness of the piezoelectric film including the central portion 72 of the piezoelectric film can be, for example, 0.5 to 10 μm. The thickness of the piezoelectric film can be determined, for example, by image analysis of a cross-sectional photograph. That is, the thickness of the piezoelectric film is preferably measured at three or more points in the in-plane direction and calculated as the average value. It is preferable to use a piezoelectric film with a thickness variation of ±5% or less.

[0049] The piezoelectric film may be an epitaxially grown film. An epitaxially grown film refers to a film epitaxially grown on a single crystal substrate. Here, epitaxial growth refers to the growth of film crystals that align with the crystal lattice of the underlying material and are aligned in the thickness direction (Z-axis direction) and in-plane directions (X-axis and Y-axis directions) during film formation. Therefore, the piezoelectric film 10, which is an epitaxially grown film, has a crystalline structure in which the crystals are aligned in all three directions (X-axis, Y-axis, and Z-axis) at high temperatures during film formation (epitaxial film). At room temperature after film formation, almost no grain boundaries are formed, and the film has a crystalline structure close to single crystal (not completely single crystal) (epitaxially grown film).

[0050] When the piezoelectric film is an epitaxially grown PZT film, it preferably contains two tetragonal domains and one rhombohedral domain, for a total of three domains. On the other hand, when the piezoelectric film is an epitaxially grown KNN film, it preferably contains two orthorhombic domains and one monoclinic domain (for a total of three domains). Furthermore, when the piezoelectric film is an epitaxially grown BCZT film, it preferably contains two tetragonal domains and two orthorhombic domains (for a total of four domains).

[0051] The piezoelectric film does not have to be an epitaxially grown film, and may be a piezoelectric thin film such as PZT, KNN, or BCZT formed by a thin film method other than epitaxial growth.

[0052] (Ferromagnetic film) The ferromagnetic film 73 is preferably made of, for example, a soft magnetic highly magnetostrictive film, which generates distortion due to the magnetostrictive effect when a magnetic field, electromagnetic wave, ultrasonic wave, or the like is applied from the outside. C Threshold magnetic field H TH It is made of a soft magnetic material with low saturation magnetostriction λ MAX It is preferable that the saturation magnetostriction λ is 5 ppm or more. MAX is more preferably 10 ppm or more.MAX Generally, a low magnetostrictive material having a magnetostrictive coefficient of 1 ppm or less is used, but it is important that the ferromagnetic film 73 of this embodiment is a soft magnetic material and has high magnetostrictive properties.

[0053] Examples of soft magnetic materials having the above characteristics include iron (Fe)-cobalt (Co)-silicon (Si)-boron (B) alloys, Fe-Si-B alloys, Fe-Co-B alloys, Fe-chromium (Cr)-Si-B alloys, Fe-nickel (Ni)-molybdenum (Mo)-B alloys, Fe-Si-B-copper (Cu)-niobium (Nb) alloys, and Co-Fe-Ni-Si-B-Mo alloys.

[0054] In this embodiment, the coercive force H C The coercive force H is preferably less than 2500 A / m. C The lower the coercive force H C It is difficult to make the coercive force H C The lower limit of the coercive force H of the soft magnetic highly magnetostrictive film also depends on the specifications of the film-forming equipment used during manufacturing. C is more preferably 1 A / m or more and less than 2500 A / m, and even more preferably 1 A / m or more and 1500 A / m or less.

[0055] Furthermore, the threshold magnetic field H TH is more preferably 1 A / m or more and less than 500 A / m, and further preferably 1 A / m or more and 350 A / m or less. TH This means the magnetic field at which a magnetostriction of 0.1 ppm occurs in a soft magnetic highly magnetostrictive film. In addition, the magnetic field sensitivity dλ / dH of a soft magnetic highly magnetostrictive film is 10 ppb m A -1 It is preferable that the concentration is 15 ppb m A or more. -1 In this embodiment, the magnetic field sensitivity dλ / dH means the amount of change in magnetostriction in an environment where a DC magnetic field of 500 A / m is applied as a bias magnetic field.

[0056] The ferromagnetic film 73 preferably includes an amorphous phase and a crystalline phase. Furthermore, in the ferromagnetic film 73 including an amorphous layer and a crystalline layer, it is more preferable that most of the crystalline phases included have a face-centered cubic (fcc) structure. However, even in this case, at least a portion of the crystalline phase may be mixed with a crystalline phase having a body-centered cubic (bcc) structure.

[0057] The thickness of the ferromagnetic film 73 is preferably within a range of 0.1 to 5 μm. The thickness of the ferromagnetic film 73 is measured in the same manner as the thickness of the central portion 72 of the piezoelectric film. The thickness of the ferromagnetic film 73 also has small variations in the in-plane direction, and can have variations similar to those of the thickness of the central portion 72 of the piezoelectric film. In this embodiment, the ratio of the thickness of the ferromagnetic film 73 to the thickness of the central portion 72 of the piezoelectric film (thickness of central portion 72 of the piezoelectric film / thickness of ferromagnetic film 73) is preferably within a range of 1 / 10 to 1 / 10.

[0058] (substrate) The substrate 40 in the magnetoelectric transducer element 30 is made up of an insulating member or the like that supports at least the laminate 32. For example, the substrate 40 may be a single crystal substrate used when epitaxially growing the piezoelectric film 10 of the laminate 32, or a substrate used when laminating the components that make up the laminate 32 by a thin film method or the like. The material of the substrate 40 can be selected from various single crystals such as Si, MgO, strontium titanate (SrTiO3), and lithium niobate (LiNbO3), and in particular, a silicon substrate whose surface is a single crystal of the Si(100) plane is preferably used.

[0059] The lower metal film, which includes the lower metal film central portion 74 and the lower metal film end portion 84, is composed of a conductive metal film such as Pt, Ag, Cu, Au, or Al. When the piezoelectric film is an epitaxially grown film, the lower metal film is also preferably an epitaxially grown film. The epitaxially grown lower metal film is preferably a metal thin film with a face-centered cubic structure such as Pt, Ir, or Au, or an oxide conductor film with a perovskite structure such as SrRuO3 (SRO) or LaNiO3. Such metal thin films and oxide conductor thin films can be epitaxially grown on a single-crystal substrate, thereby enabling the lower metal film to also be an epitaxially grown film. The lower metal film may also be composed of a laminate of the above-mentioned metal thin film and the above-mentioned oxide conductor film (e.g., Pt electrode / SrRuO3). In this case (when multiple layers are stacked), it is preferable that an oxide conductor film be present on the piezoelectric film side of the lower metal film (i.e., above in the Z-axis direction). The average thickness of the lower metal film as a whole is preferably set to 3 nm to 200 nm.

[0060] 3, an upper electrode film may be formed between the ferromagnetic film 73 and the central portion 72 of the piezoelectric film. When an upper electrode film is formed between the central portion 72 of the piezoelectric film and the ferromagnetic film 73, the upper electrode film may be made of the same material and have the same thickness as the central portion 74 of the lower metal film.

[0061] The first extraction electrode film 51 and the second extraction electrode film 53 shown in Figures 1 to 4 are made of conductive films, and there are no particular restrictions on the material or thickness. For example, the first extraction electrode film 51 and the second extraction electrode film 53 can contain conductive metals such as Ag, Cu, Au, and Al in addition to Pt. The insulating film 54 shown in Figures 1 to 4 is made of an electrically insulating film, and there are no particular restrictions on the material or thickness. For example, SiO2, Al2O3, polyimide, etc. can be used as the material of the insulating film 54.

[0062] Note that, as a vibrating body according to a modified example, unlike the vibrating body 70 shown in FIG. 2, a buffer layer may be formed below the lower metal film central portion 74 and the lower metal film end portion 84 in the Z-axis direction (i.e., between the substrate 40 and the lower metal film). By forming a buffer layer between the substrate 40 and the lower metal film, it is possible to promote epitaxial growth of films located above the buffer layer. Furthermore, the buffer layer also functions as an etching stopper layer when forming the lower space 40b in the substrate 40. When a buffer layer is formed, its thickness is preferably 5 nm to 100 nm.

[0063] 1 to 5, the vibrating body 70 functions as a vibrator having a vibration mode of a specific frequency. That is, the vibrating body 70 can generate in-plane expansion and contraction in which the vibrating body 70 expands and contracts along the XY plane, and can vibrate in an in-plane direction. Note that the vibrating body 70 can not only expand and contract in-plane, but also out-of-plane expansion and contraction in which the vibrating body 70 expands and contracts in the Z-axis direction.

[0064] The supporting arm 80 connecting the vibrating body 70 and the fixed part 41 preferably has a low rigidity relative to the vibrating body 70 so as not to hinder the in-plane expansion and contraction that occurs in the vibrating body 70. As shown in FIG. 2, for example, the width of the supporting arm 80 in the Y-axis direction is made narrower than the width of the vibrating body 70 in the Y-axis direction. Alternatively, the thickness of the supporting arm 80 in the Z-axis direction is made smaller than the thickness of the vibrating body 70 in the Z-axis direction. The product of the thickness and width of the supporting arm 80 is preferably less than 90% of that of the vibrating body 70, and more preferably less than 75%. With this configuration, it is possible to induce in-plane expansion and contraction vibrations with large amplitude, and the output of the magneto-electric conversion element 30 can be further increased.

[0065] Furthermore, the length of the support arm 80 in the X-axis direction is preferably about 1 / 4 of the vibration wavelength at which the vibrating body 70 operates. By setting the length to such an extent, energy can be efficiently trapped in the vibrating body 70, the output of the magnetoelectric conversion element 30 can be increased, and interference between multiple vibrating bodies 70 can be suppressed.

[0066] 5(b) and 5(c) is preferably lower than the resonant frequency at which the vibrating bodies 70 operate, from the viewpoint of preventing vibration of the fixed part 41 and ensuring the independence of vibration of each vibrating body 70. Also, from the viewpoint of suppressing interference between the multiple vibrating bodies 70, it is also preferable that the fundamental resonant frequency of the vibration mode of the fixed part 41, which is displaced in the same direction as the vibration direction of the vibration mode in which the vibrating bodies 70 operate, is lower than the resonant frequency at which the vibrating bodies 70 operate.

[0067] An example of a method for manufacturing the magnetoelectric transducer 30 shown in FIGS. 1 to 5 will now be described.

[0068] In manufacturing the magnetoelectric transducer 30, first, a lower metal film that will become the lower metal film central portion 74 and the lower metal film end portion 84, a piezoelectric film that will become the piezoelectric film central portion 72 and the piezoelectric film end portion 82, and a ferromagnetic film 73 are formed on a film-forming substrate such as a silicon substrate. The lower metal film, the piezoelectric film, and the ferromagnetic film can be formed by physical or chemical methods such as vapor deposition, sputtering, a sol-gel process, CVD, and PLD. Furthermore, when at least a portion of the lower metal film, the piezoelectric film, and the ferromagnetic film are formed by epitaxial growth, sputtering is preferably used. Furthermore, when the ferromagnetic film is a magnetic film composed of a soft magnetic, highly magnetostrictive film, it can be formed by a vacuum deposition method such as sputtering, vacuum evaporation, PLD, or ion beam deposition (IBD), with sputtering being preferred.

[0069] Furthermore, the lower metal film, the piezoelectric film, and the ferromagnetic film 73 formed on the film-formation substrate are patterned to form the patterns shown in Figures 2 to 4. The patterning can be performed by various etching methods such as photoetching and laser dry etching, or by a lift-off method.

[0070] After patterning, the first and second extraction electrode films 51 and 53 and the insulating film 54 are formed in a predetermined pattern as shown in FIGS. 2 to 4. Furthermore, a portion of the film-forming substrate is removed by dry etching such as Deep-RIE or anisotropic wet etching to form the substrate 40 having the lower space 40b. The film-forming substrate may be entirely removed by the etching. In this case, the vibrating body 70, the support arm 80, and the extraction electrode films 51 and 53, etc., peeled from the film-forming substrate, may be fixed to the substrate 40 prepared as separate members. Furthermore, a cover 90 as shown in FIG. 5(b) is bonded to the upper surface of the substrate 40, thereby obtaining the magnetoelectric transducer 30 shown in FIGS. 1 to 5. The cover 90 is provided primarily to protect the vibrating body 70 and the upper space 90a, but may be omitted if the magnetoelectric transducer 30 is disposed inside a device. [Example]

[0071] The magnetoelectric transducer 30 according to the first embodiment will be described in more detail below using examples, but the magnetoelectric transducer 30 is not limited to only the examples.

[0072] Example 1 1 and 5 was fabricated as the magnetoelectric transducer 30 according to Example 1, in which a plurality of vibrating bodies 70 were arranged above a plurality of lower spaces 40b formed in the substrate 40. The plurality of vibrating bodies 70 included in the magnetoelectric transducer 30 all had the same shape, and the width of each vibrating body 70 in the X-axis direction was 200 μm, and the width of each vibrating body 70 in the Y-axis direction was 200 μm.

[0073] Each vibrating body 70 was configured from a film laminate including a piezoelectric film central portion 72 made of epitaxially grown PZT and a ferromagnetic film 73 made of an Fe-Co-Si-B alloy having a crystalline phase and an amorphous phase. The thickness of the piezoelectric film central portion 72 was 1 μm, and the thickness of the ferromagnetic film 73 was 0.5 μm. The height of the fixed portion 41 shown in FIG. 5(c) (the distance from the surface on the positive side of the Z-axis of the substrate 40 to the upper end 41a of the fixed portion 41) was 300 μm.

[0074] The number of vibrating bodies 70 included in the magnetoelectric transducer 30 according to Example 1 was 45, and the 45 vibrating bodies 70 were arranged along the X-axis direction and the Y-axis direction, and the vibrating bodies 70 were wired in series. The overall dimensions of the magnetoelectric transducer 30 were 1 cm × 1 cm.

[0075] In Example 1, the side surface 41b of the fixing portion 41 shown in FIG. 5(c) was formed at an angle of 5 degrees (target angle) from the Z-axis direction. The inclination of the side surface 41b was formed by adjusting the output and time of the silicon etching and the formation of a protective film, which is a known adjustment method for etching, when deep silicon etching was performed from the back surface (the surface on the negative Z-axis side) of the substrate 40 by the Deep-RIE method. The shape of the side surface 41b of the fixing portion 41 was measured by taking a part of a sample prepared at the same time as the sample according to the example and observing the cross section with a scanning microscope.

[0076] A magnetoelectric transducer according to a comparative example was fabricated in which only the shape of the fixed portion on the substrate was different, but the remaining parts were the same. The magnetoelectric transducer according to the comparative example differs from the magnetoelectric transducer 30 according to the example only in that the cross section of the fixed portion is rectangular and the side surface of the fixed portion rises approximately parallel to the Z-axis direction.

[0077] (shape evaluation) The shape of the fixed portion 41 of the substrate 40 in the magnetoelectric conversion element 30 according to Example 1 was measured. The cross-sectional shape of the fixed portion 41 in the XZ cross section was approximately trapezoidal as shown in FIG. 5(c). The inclination angle of the side surface 41b of the fixed portion 41 with respect to the Z-axis direction was 5 degrees (with an error of ±1 degree). The width of the fixed portion 41 in the X-axis direction was 100 μm at the same height as the upper end 41a to which the support arm 80 was fixed, and 150 μm at the lower end 41c, which was the same height as the end of the substrate 40 in the negative Z-axis direction. The length of the fixed portion 41 in the Y-axis direction was 300 μm at both the upper end 41a and the lower end 41c.

[0078] That is, in the magnetoelectric transducer 30 according to the first embodiment, the cross-sectional area of ​​the first cross section 42 at the first distance L1 (L1=0 μm) from the upper end 41 a is 3000 μm 2 The cross-sectional area of ​​the second cross section 43, which is a second distance L2 (L2=300 μm) from the upper end 41 a, is 4500 μm 2 As described above, it was confirmed that the cross-sectional area of ​​the fixed portion 41 of the magnetoelectric transducer 30 according to Example 1, which is parallel to the main surface 70a of the vibrating body 70, gradually narrows as the distance from the upper end 41a of the fixed portion 41 decreases.

[0079] On the other hand, in the magnetoelectric transducer according to Comparative Example 1, the cross-sectional shape of the fixed portion was approximately rectangular, and the inclination angle of the side surface of the fixed portion with respect to the Z-axis direction was 0 degrees (with an error of ±1 degree). Also, in the magnetoelectric transducer according to Comparative Example 1, the cross-sectional area of ​​the cross section parallel to the main surface 70a of the vibrating body was the same at the upper and lower ends of the fixed portion, 3000 μm 2 It was.

[0080] (measuring resonance frequency) The vibration characteristics of the vibrating body 70 of the magnetoelectric transducer 30 according to Example 1 and the magnetoelectric transducer according to Comparative Example 1 were measured using an impedance analyzer. As a result, it was confirmed that the vibrating bodies 70 of both Example 1 and Comparative Example 1 have an operating resonant frequency of 5 MHz and are bulk acoustic wave vibrators that vibrate in an elastic wave spreading vibration mode. The vibration direction of the vibration mode in which the vibrating body 70 vibrates in an elastic wave spreading vibration mode was the in-plane horizontal direction.

[0081] In the magnetoelectric transducer 30 according to Example 1, the primary resonance frequency (natural frequency) of the fixed part 41 was 120 KHz, which was the resonance frequency at which the vibrating body 70 operates, and was therefore confirmed to be lower than 5 MHz. Furthermore, the primary resonance frequency of the fixed part 41 was a vibration mode in which the fixed part 41 displaces in the in-plane horizontal direction, which is the same direction as the vibration mode in which the vibrating body 70 operates. Therefore, in the magnetoelectric transducer 30 according to Example 1, it was confirmed that the fundamental resonance frequency (120 KHz) of the vibration mode of the fixed part 41 displaced in the same direction as the vibration direction of the vibration mode in which the vibrating body 70 operates is lower than the resonance frequency (5 MHz) at which the vibrating body 70 operates.

[0082] (Measurement of output voltage) A magnetic field of 5 MHz, which is the same frequency as the resonant frequency at which the vibrating body 70 operates, was applied to the magnetoelectric transducer 30 according to Example 1 and the magnetoelectric transducer according to Comparative Example 1, and the output of each element was measured. As a result, an output voltage of 50 mV was detected in the magnetoelectric transducer 30 according to Example 1, while an output voltage of 30 mV was detected in the magnetoelectric transducer according to Comparative Example 1.

[0083] Second embodiment 6(a) and 6(b) are schematic diagrams showing a part of the magnetoelectric transducer 130 according to the second embodiment, and correspond to FIGS. 5(a) and 5(b) showing the magnetoelectric transducer 30 according to the first embodiment. FIG. 6(a) is a plan view seen from the positive side of the Z axis, and FIG. 6(b) is a cross-sectional view taken along a plane parallel to the XZ plane. Note that the cover 90 shown in FIG. 6(b) is omitted in FIG. 6(a) for ease of explanation.

[0084] 6(a) and 6(b), the magnetoelectric conversion element 130 according to the second embodiment differs from the magnetoelectric conversion element 30 according to the first embodiment in that the fixed portion of the substrate 140 has fixed portion upper portions 141 that divide the lower spaces 140b corresponding to each vibrating body 70 in the X-axis direction in the cross-sectional view shown in Fig. 6(b), and fixed portion common bottom portions 146 that connect the multiple fixed portion upper portions 141 below the fixed portion upper portions 141 (in the negative Z-axis direction). However, the parts other than the substrate 140 are similar to the magnetoelectric conversion element 30 shown in Fig. 5(a) and 5(b). The magnetoelectric conversion element 130 according to the second embodiment will be described mainly with respect to the differences from the magnetoelectric conversion element 30 according to the first embodiment, and a description of the commonalities with the magnetoelectric conversion element 30 will be omitted.

[0085] 6(a), the support arm 80 connected to the vibrating body 70 is fixed to an upper end 141a of the fixed portion upper part 141, and the fixed portion upper part 141 supports the vibrating body 70 so that it can vibrate via the support arm 80. However, while the fixed part 41 shown in FIG. 5(a) extends in the Y-axis direction and is connected to the connection part 48 of the substrate 40, the fixed portion upper part 141 is not connected to the connection part 148 of the substrate 140 and is spaced apart from the connection part 148.

[0086] The substrate 140 is formed with a plurality of lower spaces 140b, between which at least a portion of the fixed portion 140 (fixed portion upper portions 141) is disposed. As shown in FIG. 6(b), the lower ends of the fixed portion upper portions 141 are connected to the fixed portion common bottom portion 146. In other words, the multiple fixed portion upper portions 141 protrude upward from the upper surface of the fixed portion common bottom portion 146, and the support arm portion 80 is fixed to the upper ends 141a of the fixed portion upper portions 141. Furthermore, the fixed portion upper portions 141 and the fixed portion common bottom portion 146 are made of a common material such as Si, and are an integrated member with no joints.

[0087] 6(b), fixed portion upper portion 141 has a substantially trapezoidal shape in a cross section (longitudinal cross section) perpendicular to main surface 70a of the vibrating body and parallel to the X-axis direction. Therefore, like fixed portion 41 shown in FIG. 6(c), fixed portion upper portion 141 has a cross-sectional area of ​​a first cross section that is a first distance from upper end 141a that is narrower than a second cross section that is a second distance from upper end 141a that is longer than the first distance.

[0088] The magnetoelectric transducer 130 according to the second embodiment also provides the same effects as the magnetoelectric transducer 30 according to the first embodiment.

[0089] Third embodiment 7(a) and 7(b) are schematic diagrams showing a part of a magnetoelectric transducer 230 according to the third embodiment, and correspond to FIGS. 6(a) and 6(b) showing the magnetoelectric transducer 130 according to the second embodiment. FIG. 7(a) is a plan view seen from the positive Z-axis direction, and FIG. 7(b) is a cross-sectional view taken along a plane parallel to the XZ plane. Note that the cover 90 shown in FIG. 7(b) is omitted in FIG. 7(a) for ease of explanation.

[0090] 7(a) and 7(b), the magnetoelectric conversion element 230 according to the third embodiment has an upper fixed portion 241 that is different from the upper fixed portion 141 shown in Fig. 6(b), but is otherwise similar to the magnetoelectric conversion element 130 according to the second embodiment. The magnetoelectric conversion element 230 according to the third embodiment will be described mainly with reference to the differences from the magnetoelectric conversion element 130 according to the second embodiment, and a description of the commonalities with the magnetoelectric conversion element 130 will be omitted.

[0091] As shown in Fig. 7(a), the support arm 80 connected to the vibrating body 70 is fixed to an upper end 241a of the fixed portion upper part 241 of the substrate 240, and the fixed portion upper part 241 supports the vibrating body 70 so that it can vibrate via the support arm 80. As shown in Fig. 7(b), the lower end of the fixed portion upper part 241 is connected to the fixed portion common bottom part 146, but unlike the fixed portion upper part 141 shown in Fig. 6(b), it is made of a different material from the fixed portion common bottom part 146 and has a higher specific gravity than the fixed portion common bottom part 146.

[0092] The upper part 241 of the fixed part shown in Figure 7(b) can be produced, for example, by joining the upper part 241 of the fixed part made of a different material to the upper surface of the flat common bottom part 146 of the fixed part, or by forming a thin film of the upper part 241 of the fixed part made of a different material.

[0093] In the magnetoelectric transducer 230 according to the third embodiment, the specific gravity of the fixed portion upper part 241 that supports the vibrating body 70 is greater than that of other parts of the substrate 40, and therefore vibration of the fixed portion upper part 241 can be prevented. In addition, the magnetoelectric transducer 230 according to the third embodiment has common features with the magnetoelectric transducer 130 according to the second embodiment, and therefore has the same effects as the magnetoelectric transducer 130.

[0094] Fourth embodiment Fig. 8 is a schematic cross-sectional view showing a part of the magnetoelectric conversion element 330 according to the fourth embodiment, and corresponds to Fig. 6(b) relating to the magnetoelectric conversion element 130 according to the second embodiment. Fig. 8 is a cross-sectional view of the magnetoelectric conversion element 330 taken along a section parallel to the XZ plane.

[0095] 8, in the magnetoelectric conversion element 330 according to the fourth embodiment, the shape of the fixed portion upper part 341 on the substrate 340 is different from the fixed portion upper part 141 shown in Fig. 6(b), but in other respects it is similar to the magnetoelectric conversion element 130 according to the second embodiment. The magnetoelectric conversion element 330 according to the fourth embodiment will be described mainly with reference to the differences from the magnetoelectric conversion element 130 according to the second embodiment, and a description of the commonalities with the magnetoelectric conversion element 130 will be omitted.

[0096] As shown in Fig. 8, in the magnetoelectric conversion element 330 according to the fourth embodiment, at least a portion of the side surface 341c of the fixed portion upper part 341 is curved. In this way, even when the side surface 341c of the fixed portion upper part 341 is curved, the rigidity of the fixed portion upper part 341 can be increased and vibration of the fixed portion upper part 341 can be prevented, similar to the case where the side surface of the fixed portion upper part 141 is flat as in the magnetoelectric conversion element 130 shown in Fig. 6(b). Furthermore, the magnetoelectric conversion element 330 according to the fourth embodiment has the same effects as the magnetoelectric conversion element 130 according to the second embodiment in terms of the commonalities therebetween.

[0097] Fifth embodiment Fig. 9 is a schematic diagram showing a part of a magnetoelectric transducer 430 according to the fifth embodiment, and corresponds to Fig. 5(b) relating to the magnetoelectric transducer 30 according to the first embodiment. Fig. 9 is a cross-sectional view taken along a cross section parallel to the XZ plane.

[0098] 9, the magnetoelectric conversion element 430 according to the fifth embodiment differs from the magnetoelectric conversion element 30 according to the first embodiment in that the fixed portion of the substrate 440 has fixed portion upper portions 441 that divide the lower spaces 440b corresponding to each vibrating body 70 in the X-axis direction, and a fixed portion common bottom portion 446 that connects the multiple fixed portion upper portions 441 below the fixed portion upper portions 141 (in the negative Z-axis direction), but the parts other than the substrate 440 are similar to the magnetoelectric conversion element 30 shown in FIG. The magnetoelectric conversion element 430 according to the fifth embodiment will be described mainly with respect to the differences from the magnetoelectric conversion element 30 according to the first embodiment, and a description of the commonalities with the magnetoelectric conversion element 30 will be omitted.

[0099] In the magnetoelectric transducer 430, the fixed portion upper parts 441 support the vibrating body 70 so that the vibrating body 70 can vibrate via the support arm parts 80. As shown in Fig. 9, the lower ends of the fixed portion upper parts 441 are connected to the fixed portion common bottom part 446. In other words, the multiple fixed portion upper parts 441 protrude upward from the upper surface of the fixed portion common bottom part 446, and the support arm parts 80 are fixed to the upper ends 141a of the fixed portion upper parts 441.

[0100] 9, the cross-sectional area of ​​the fixed portion upper part 441 taken along a cross section (first cross section) parallel to the main surface 70a of the vibrating body 70 is constant. However, the cross-sectional area of ​​the first cross section of the fixed portion upper part 141 is narrower than the cross-sectional area of ​​the second cross section of the fixed portion common bottom part 446 taken along a second cross section parallel to the main surface 70a of the vibrating body 70 and at a greater distance from the upper end 441a than the first cross section. The wide cross-sectional area of ​​the fixed portion common bottom part 446 increases the rigidity of the fixed portion of the magneto-electric transducer element 430, making it possible to prevent vibration.

[0101] The fixing portion of the substrate 440 has a step surface 447 that connects a side surface 441c (first side surface) of the fixing portion upper portion 441 as a first portion including the first cross section and a side surface 446a (second side surface) of the fixing portion common bottom portion 446 as a second portion including the second cross section. In the cross section shown in Fig. 9, the step surface 447 forms the bottom surface of the lower space 440b.

[0102] The magnetoelectric transducer 430 according to the fifth embodiment also has the same effects as the magnetoelectric transducer 30 according to the first embodiment in the parts common to both the magnetoelectric transducer 430 and the magnetoelectric transducer 30 according to the first embodiment.

[0103] Sixth embodiment Fig. 10 is a schematic cross-sectional view showing a part of a magnetoelectric transducer 530 according to the sixth embodiment, and corresponds to Fig. 9 relating to the magnetoelectric transducer 430 according to the fifth embodiment. Fig. 10 is a cross-sectional view of the magnetoelectric transducer 530 taken along a section parallel to the XZ plane.

[0104] 10, a magnetoelectric transducer 530 according to the sixth embodiment has a cover 590 with a shape different from that of the cover 90 shown in Fig. 9, but is otherwise similar to the magnetoelectric transducer 430 according to the fifth embodiment. The magnetoelectric transducer 530 according to the sixth embodiment will be described mainly with reference to the magnetoelectric transducer 430 according to the fifth embodiment, and a description of the commonalities with the magnetoelectric transducer 430 will be omitted.

[0105] 10, the cover portion 590 of the magnetoelectric transducer 530 according to the sixth embodiment has a cover portion pillar portion 590c extending downward from a cover portion upper portion 590b. The lower end of the cover portion pillar portion 590c is connected to the upper end 441a of the fixed portion upper portion 441, and the upper spaces 590a above two adjacent vibrating bodies 70 are separated by the cover portion pillar portion 590c. In the magnetoelectric transducer 530 having such a cover portion 590, the upper space 590a and the lower space 440b that house the vibrating bodies 70 are separated for each vibrating body 70.

[0106] The magnetoelectric transducer 530 according to the sixth embodiment has the same advantages as the magnetoelectric transducer 430 according to the fifth embodiment in terms of the commonalities therebetween.

[0107] Seventh embodiment Fig. 11 is a schematic cross-sectional view showing a part of a magnetoelectric transducer 630 according to the seventh embodiment, and corresponds to Fig. 9 relating to the magnetoelectric transducer 430 according to the fifth embodiment. Fig. 11 is a cross-sectional view of the magnetoelectric transducer 530 taken along a section parallel to the XZ plane.

[0108] 11, the magnetoelectric transducer 630 according to the seventh embodiment differs from the magnetoelectric transducer 430 according to the sixth embodiment in that it has a case part 690 instead of the cover part 90 shown in Fig. 9, but is otherwise similar to the magnetoelectric transducer 430. The magnetoelectric transducer 630 according to the seventh embodiment will be described mainly with respect to the differences from the magnetoelectric transducer 430 according to the fifth embodiment, and a description of the commonalities with the magnetoelectric transducer 430 will be omitted.

[0109] 11, a magnetoelectric transducer 630 according to the seventh embodiment has a case 690 that houses the vibrating body 70 and the substrate 440, instead of the cover 590. The case 690 has a case bottom 690c that supports the bottom surface of the substrate 440, and a case upper part 690b that covers the sides and above of the substrate 440 and the vibrating body 70.

[0110] Case section 690 has a housing space formed therein by combining case bottom section 690c and case top section 690b, and other components such as vibrating body 70 and substrate 440 are placed in this housing space.

[0111] The magnetoelectric transducer 630 according to the seventh embodiment has the same advantages as the magnetoelectric transducer 430 according to the fifth embodiment in terms of the commonalities therebetween.

[0112] The present invention has been described above by giving embodiments and examples, but it goes without saying that the laminate according to the present invention is not limited to the above-described embodiments and examples, and includes other embodiments and modified examples.

[0113] For example, while vibrating body 70 has a substantially rectangular shape in plan view, the shape of vibrating body 70 is not limited to this and may be an elliptical, circular, meandering, or spiral shape in plan view. Similarly, the shape of supporting arm 80 is not limited to a substantially rectangular (strip) shape in plan view and may be a meandering, crank, doughnut (hollow circle or polygon), or arc shape in plan view. Furthermore, the arrangement of multiple vibrating bodies 70 is not limited to the matrix arrangement shown in FIG. 1 and may be concentric, radial, or other arrangements. [Explanation of symbols]

[0114] 30, 130, 230, 330, 430, 530, 630...Magnetoelectric conversion element 40, 140, 240, 340, 440... PCB 41...Fixed part 41a, 141a, 241a...Top end 41b...side 41c…lower end 42…First cross section L1...first distance 43…Second cross section L2: Second distance 48, 148...Connection 49...Frame 40b, 140b…lower space 70...Vibration body 70a…main surface 72...Center part of piezoelectric film 73...Ferromagnetic film 74...Central part of lower metal film 80...Support arm 82...Piezoelectric film end 84…Bottom metal film edge 51...First extraction electrode film 53…Second extraction electrode film 54...insulating film 90, 590...Cover part 90a, 590a...Upper space 94...Gap 96…Wiring section 141, 241, 341, 441...Top of fixed part 146, 446…Fixed part common bottom 341c, 441c...Side of upper fixed part 446a...Side of the common bottom of the fixed part 447...Step surface 590b...Upper part of cover 590c...Cover and pillar parts 690…Case section 690b…Top of case 690c…Case bottom

Claims

1. A substrate having a plurality of lower spaces between which at least a portion of a fixing portion is disposed; a plurality of vibrating bodies provided in correspondence with the lower space, supported in a vibratory manner on the lower space via supporting arms connected to the fixing portion, and having magnetoelectric conversion properties; Each of the lower spaces is connected to an upper space, which is a space above the corresponding vibrating body, via a gap between the vibrating body and the substrate, a cross-sectional area of ​​a first cross section of the fixed portion that is parallel to a main surface of the vibrating body and is a first distance from an upper end of the fixed portion is narrower than a cross-sectional area of ​​a second cross section of the fixed portion that is parallel to a main surface of the vibrating body and is a second distance from the upper end of the fixed portion that is longer than the first distance; A magnetoelectric transducer, characterized in that a primary resonance frequency of said fixed portion is lower than a resonance frequency at which said vibrating body operates.

2. A substrate having a plurality of lower spaces between which at least a portion of the fixed portion is disposed; a plurality of vibrating bodies provided in correspondence with the lower space, supported in a vibratory manner on the lower space via supporting arms connected to the fixing portion, and having magnetoelectric conversion properties; Each of the lower spaces is connected to an upper space, which is a space above the corresponding vibrating body, via a gap between the vibrating body and the substrate, a cross-sectional area of ​​a first cross section of the fixed portion that is parallel to a main surface of the vibrating body and is a first distance from an upper end of the fixed portion is narrower than a cross-sectional area of ​​a second cross section of the fixed portion that is parallel to a main surface of the vibrating body and is a second distance from the upper end of the fixed portion that is longer than the first distance; A magnetoelectric transducer having a fundamental resonance frequency of a vibration mode of the fixed portion displaced in the same direction as the vibration direction of the vibration mode in which the vibrating body operates, which is lower than the resonance frequency in which the vibrating body operates.

3. 3. The magnetoelectric transducer according to claim 1, wherein the fixed portion has a transition change portion in which a cross-sectional area of ​​a cross section parallel to a main surface of the vibrating body at the fixed portion transitionally narrows as the distance from the upper end of the fixed portion decreases.

4. The magnetoelectric transducer according to claim 1 , wherein the fixed portion has a step surface connecting a first side surface of a first portion including the first cross section and a second side surface of a second portion including the second cross section.

5. 5. A magnetoelectric transducer according to claim 1, wherein the vibrating body has a film laminated portion including a piezoelectric film and a ferromagnetic film.

Images