58results about How to "Improve magnetoelectric properties" patented technology

The invention discloses laminated ferroelectric/magnetic multiferroic and magnetoelectric composite film and preparation method thereof. The film comprises a substrate, a ferroelectric oxide layer and a magnetic oxide layer, and also a buffer layer positioned between the substrate layer and the ferroelectric oxide layer or the magnetic oxide layer. The layer can be LaNiO3, YBa2Cu3O7-x or SrRuO3, among which LaNiO3 is preferred. The preparation method comprises the following steps: firstly, buffer layer sol is prepared; secondly, the buffer layer sol is uniformly coated on the substrate to obtain the buffer layer; thirdly, sol of the ferroelectric oxide layer and the magnetic oxide layer is respectively prepared; fourthly, the sol obtained in step 3 is coated on the buffer layer, and then the end product is obtained. After the composite film is introduced into the buffer layer, the stress restraint of the substrate to the composite film is effectively reduced, the magnetoelectric coupling performance of the composite film with laminated structure is obviously enhanced, the cost is reduced, the preparation technique is simple, the requirement on the equipment is low, and the compatibility with the prior technique is good.

The invention relates to a permanent-magnetic brushless direct current motor which comprises a shell, a front end cover, a rear end cover, a stator, a rotor, and a position sensor, wherein the stator comprises a stator iron core and a winding, the inner side of the stator iron core is provided with a plurality of tooth grooves, the winding passes through the tooth grooves; the rotor comprises a rotating shaft, a rotor iron core and at least one pair of magnetic steels, the rotor iron core is sleeved on the rotating shaft, the magnetic steels are arranged at the periphery of the rotor iron core; and the position sensor comprises a circuit board and a Hall element connected with the circuit board, wherein magnetic conduction inlaid strips used for magnetic conduction are arranged in the tooth grooves of the stator iron core, the cross sections of the magnetic steels of the rotor have an arc shape the thickness at the middle part of which is more than those at both sides, and the Hall element of the position sensor is close to end parts of the magnetic steels of the rotor and takes the magnetic leakage of the magnetic steels of the rotor as a running signal of the Hall element. The permanent-magnetic brushless direct current motor can effectively save production cost and improve the working performance of the motor.

The invention discloses a method for preparing and transferring a multilayer barium titanate and multilayer cobalt ferrite magnetoelectric composite film. The problems that the substrate clamping effect and electric leakage cannot be simultaneously reduced by the composite material of the conventional structures 1-3 are mainly solved. The method comprises the following implementation steps: depositing a magnesium oxide film on a sapphire substrate, and alternatively depositing a multilayer cobalt ferrite film and a multilayer barium titanate film on the substrate; spinning polymethyl methacrylate on the surface of the final barium titanate film, and removing a single crystal magnesium oxide film by using an ammonium sulfate solution, so that the magnetoelectric composite film attached to polymethyl methacrylate is separated from the sapphire substrate; and transferring the magnetoelectric composite film separated from the sapphire substrate onto a subsequent needed substrate, thereby obtaining a self-supported magnetoelectric film compounded by the multilayer cobalt ferrite film and the multilayer barium titanate film. The multilayer barium titanate and multilayer cobalt ferrite composite film disclosed by the invention is large in surface coupling property, the magnetic and electrical properties are enhanced, the substrate clamping and electric leakage problems are reduced, and the method can be used for preparing a magnetoelectric sensor.

The invention relates to a nickel/ piezoelectric ceramic layered composite material with magneto-electric effect and its relative preparing method. Wherein, said composite material is compounded by the nickel plate and piezoelectric ceramic plates by the method of adhering while the thickness rate between nickel layer and piezoelectric ceramic layer is 0.1-5. The preparing method comprises that plating gold or silver electrode on the upper and lower surfaces of piezoelectric ceramic plate whose thickness is 0.2-1mm and the electrode will be polarized along the direction of thickness of piezoelectric ceramic plate; utilizing the organic conductive binder to bind the nickel plate and the piezoelectric ceramic plate whose thickness ranges from 0.1-1 mm to be solidified in room temperature to attain said composite material. The inventive composite material, compared to present electromagnetic material, has high electromagnetic performance, simple preparing process, lower cost, stable property and higher designable ability, which can change the electromagnetic property of material via changing the size and the layer pattern of composite structure.

The invention belongs to the technical field of ceramic synthesis and provides a method for preparing a strontium lanthanum manganate/copper calcium titanate composite magnetoelectric ceramic materialby virtue of a sol-gel method. The method comprises the steps of respectively preparing lanthanum strontium manganite (LSMO) precursor powder, copper calcium titanate and CCTO precursor powder by virtue of the sol-gel method, mixing the LSMO precursor powder with the CCTO precursor powder, adding an adhesive, uniformly mixing, pressing to form a ceramic blank, and sintering a ceramic blank, so asto obtain a strontium lanthanum manganate/copper calcium titanate (LSMO-CCTO) composite magnetoelectric ceramic sample. The method has the beneficial effects that the raw materials are low in cost; components in the reaction process are controllable, and an impure phase is avoided; the gelling time is short; a preparation process is simple, and the dielectric property and magnetism of the ceramicsample have very strong regularity; a ceramic wafer is high in density and grain uniformity; and the process is simple and easy for industrial production, the prepared ceramic sample is high in density and grain uniformity and excellent in magnetoelectric performance.

The invention discloses a magnetoelectric sensor, which comprises a magnetoelectric sensor body compounded by a magnetostrictive material layer, a piezoelectric material layer and powder with high magnetic conductivity. In the magnetoelectric sensor, a composite layer of the powder with high magnetic conductivity and a magnetostrictive material is adopted, the magnetoelectric properties in various sections tend to be consistent and the integral performance is optimized; the obtained magnetoelectric efficiency of the magnetoelectric sensor is improved by 20 percent compared with that of a magnetoelectric sensor not provided with the composite layer; and the detection performance of the magnetoelectric sensor is greatly improved.

A crystalline modifying method for the polymer used for piezoelectric ceramic-polymer composition and ferromagnetic material-polymer composition to improve their piezoelectric or ferromagnetic performance includes such steps as preparing nucleator solution of non-crystal polymer, spraying it onto non-crystal polymer powder, heat treating, airflow grinding, proportionally mixing it with piezoelectric ceramic powder and ferromagnetic powder, cold die pressing, hot die pressing and annealing.

The invention discloses a spherical shell laminar magneto-electric composite material structure and a manufacturing method, and relates to the design and manufacture method of an isotropic magneto-electric effect laminar magneto-electric composite material structure. The method comprises the following steps: hemispherical shell piezoelectric ceramic is achieved through compression molding and sintering, after the high-temperature polarizing is performed, metallizing is performed by adopting the chemical plating method, two metallized piezoelectric ceramic hemispherical shells are bonded into a complete piezoelectric ceramic hemispherical shell through the strong glue, and then the shell is laid in the prepared electroplating solution to be electroplated till a magnetic layer with the required thickness is electroplated, thereby the spherical shell laminar magneto-electric composite material is achieved. Compared with the prior simple laminar composite material, such as a flat plate, because the dimensions of the structure in the three-dimensional direction are identical, the magneto-electric performances of the structure in all directions are identical, and by adopting the isotropic magneto-electric performance, the spherical shell laminar magneto-electric composite material can be applied to the magnetic field detection in the unknown directions.

The invention provides a Bi[0.85-x]Pr0.15AExFe0.97Mn0.03O3 ferroelectric film and a preparation method thereof. The method comprises the following steps: preparing a Bi[0.85-x]Pr0.15AExFe0.97Mn0.03O3 precursor solution from bismuth nitrate, praseodymium nitrate, hydrogen nitrate AE, ferric nitrate and manganous nitrate, wherein AE is Sr, Ca or Ba, and x=0.02-0.05; spinning the precursor solution on a substrate; and then spinning, drying and annealing, so as to obtain the Bi[0.85-x]Pr0.15AExFe0.97Mn0.03O3 ferroelectric film. The Bi[0.85-x]Pr0.15AExFe0.97Mn0.03O3 ferroelectric film is simple in demands on equipment; the experiment condition is easy to achieve; the doping amount is easy to control; the ferroelectric property of the film can be greatly improved; and the prepared Bi[0.85-x]Pr0.15AExFe0.97Mn0.03O3 ferroelectric film is good in uniformity, low in leakage current, and low in coercive field, and has relatively high remanent polarization.

The invention discloses a layered magnetoelectric composite material and a preparation method thereof. The preparation method comprises the following steps: granulating 0.65BaTiO3-0.35(Na0.5Bi0.5)TiO3 powder and BiY2Fe5O12 powder respectively, then carrying out compression moulding in a mould in a manner of 2-2 composite barrier layer superposition arrangement, then removing a PVA adhesive, and sintering at 1100-1150 DEG C to obtain the layered magnetoelectric composite material. According to the layered magnetoelectric composite material and the preparation method thereof disclosed by the invention, because the 0.65BaTiO3-0.35(Na0.5Bi0.5)TiO3 powder and the BiY2Fe5O12 powder are moulded in the manner of 2-2 composite barrier layer superposition arrangement to co-sinter a ferroelectric phase and a ferromagnetic phase in a layered composite manner, inter-reaction between the two phases can be effectively suppressed, thus keeping the respective characteristics, and enabling the layered magnetoelectric composite material to be good in both ferroelectricity and ferromagnetism.

The invention relates to a microwave dielectric ceramic material with high magnetic conductivity and a preparation method thereof. The ceramic material comprises a complex system (1-x)A(GazNb1-z)yTi1-yO3/(x)B(MnO4) composed of a main body A(GazNb1-z)yTi1-yO3 and a complex B(MnO4)3 wrapping the main body, wherein x is more than or equal to 0.20 mol but less than or equal to 0.50 mpl, and y is morethan or equal to 0.50 mol but less than or equal to 1.00 mol; A in the main body is one or more of Ni, Zn, Pb or Co; and B in the complex is one or more of Y, Yb, Fe, Ce, La or Lu. The preparation method of the microwave dielectric ceramic material provided by the invention adopts a microwave assisted sintering method, and the microwave dielectric ceramic material prepared by the method has a bimorphic crystal structure and a good microwave absorption property, and is low in electromagnetic loss, low in dielectric constant, high in magnetic conductivity and high in sintering speed.

The invention relates to a method for increasing a magnetoelectric property of a gradient material, comprising the step of preparing Ni-based alloy and piezoelectric ceramics into a gradient material, wherein the Ni-based alloy is Ni/Mn/Ti, and the piezoelectric ceramics is PZT (Lead Zirconate Titanate) and belongs to ferroelectric ceramics. Compared with the traditional gradient material, the gradient material provided by the invention has the characteristics of high magnetoelectric property, simple preparation process, stabile property, strong designability, and by changing the method for designing and preparing the material, the magnetoelectric property of the material can be obviously improved.

The invention discloses a Ca(Zn1/3Nb2/3)O3-based high-frequency layered magnetoelectric composite material and a preparation method thereof. The preparation method comprises the following steps: granulating Ca(Zn1/3Nb2/3)O3 powder and Ni0.8Zn0.2Fe2O4 powder, and pressing and molding the powder in a mold according to a 2-2 composite layered superposition arrangement mode; and discharging a PVA adhesive, and sintering at the temperature of 1250-1300 DEG C, thereby obtaining the Ca(Zn1/3Nb2/3)O3-based high-frequency layered magnetoelectric composite material. Because the Ca(Zn1/3Nb2/3)O3 powder and Ni0.8Zn0.2Fe2O4 powder can be arranged according to the 2-2 composite layered superposition arrangement mode, and a ferroelectric phase and a ferromagnetic phase are co-fired together by virtue of a layered compounding mode, mutual reaction between the two phases can be effectively inhibited, and the respective characteristics are maintained. Therefore, the composite material has high dielectric properties and also has good ferromagnetic properties.

The present invention is method of raising the piezoelectric performance and magnetoelectric performance of composite material with cross-linking polymer. The cross-linking polymer for the composite material may be polyvinylidene fluoride, polyethylene, epoxy resin, phenolic resin, unsaturated polyester resin, rubber or nylon. The present invention features that linear polymer is made to form crosslinked structure chemically or through irradiation. The chemical crosslinking process is to adding crosslinking agent or initiator into the composite material and the composite material is formed through mixing and hot pressing. The irradiating crosslinking process includes mixing the cross-linking polymer with the composition material, cold pressing to form at room temperature, and irradiating for crosslinking the polymer in the composite material.

The invention discloses a Ba0.9Ca0.1Ti0.9Zr0.1O3/Co0.8Ni0.1Zn0.1Fe2O4 layered magnetoelectric composite and a preparation method thereof. After Ba0.9Ca0.1Ti0.9Zr0.1O3 powder and Co0.8Ni0.1Zn0.1Fe2O4 powder are granulated, the Ba0.9Ca0.1Ti0.9Zr0.1O3 powder and the Co0.8Ni0.1Zn0.1Fe2O4 powder are pressed and formed in a mold in a 2-2 compounding layered superimposing arrangement manner, then, a PVA adhesive is discharged, the mixture is sintered at the temperature of 1,100-1,150 DEG C, and the layered magnetoelectric composite is obtained. The Ba0.9Ca0.1Ti0.9Zr0.1O3 powder and the Co0.8Ni0.1Zn0.1Fe2O4 powder are prepared in a 2-2 compounding manner, two phases are sintered in the absence of organic adhesives, the layered composite with the two phases better combined is finally obtained, the reaction between the two phases and mutual dispersion of elements are effectively controlled, and the composite not only has ferroelectric properties and ferromagnetic properties, but also has high magnetoelectric coupling coefficients.

A layered magnetoelectric composite material with high Curie temperature and high magnetoelectric coupling performance and its preparation method, comprising Li _0.058 (Na _0.535 K _0.48 ) _0.942 NbO ₃ Powder, Co _0.6 Zn _0.4 Fe _1.7 mn _0.3 o ₄ After the powder is granulated, it is pressed and formed in a mold according to the stacked arrangement of 2-2 composite barrier layers, and then the PVA binder is discharged, and sintered at 1020-1040°C to obtain a layered magnetoelectric composite material. In the present invention, since Li _0.058 (Na _0.535 K _0.48 ) _0.942 NbO ₃ Powder, Co _0.6 Zn _0.4 Fe _1.7 mn _0.3 o ₄ The powder is superimposed and arranged in a 2-2 composite barrier layer, and the ferroelectric phase and the ferromagnetic phase are co-fired together in a layered composite manner, so that it has a higher Curie temperature, better ferroelectric properties and magnetic properties. electric effect.

The invention discloses a CoFe2O4/BaTiO3-(Na0.5Bi0.5)TiO3 material and a preparation method thereof. The preparation method comprises the following steps: preparing 0.65BaTiO3-0.35(Na0.5Bi0.5)TiO3 powder with barium carbonate, titania, bismuth oxide and sodium carbonate as raw materials, carrying out granulation on CoFe2O4 powder and the 0.65BaTiO3-0.35(Na0.5Bi0.5)TiO3 powder, carrying out compression moulding in a die according to a 2-2 compounding layering staking arrangement mode, discharging rubber, and calcining. According to the CoFe2O4/BaTiO3-(Na0.5Bi0.5)TiO3 material and the preparation method thereof disclosed by the invention, as a ferroelectric phase and a ferromagnetic phase are co-fired together in a layering compounding mode according to the 2-2 compounding layering staking arrangement mode, mutual reaction between the ferroelectric phase and the ferromagnetic phase can be effectively inhibited so as to keep respective characteristics, and the CoFe2O4/BaTiO3-(Na0.5Bi0.5)TiO3 material is good in both ferroelectricity and ferromagnetism.

The invention discloses bismuth ferrite-based ceramic with excellent magnetoelectric properties and a preparation method of the bismuth ferrite-based ceramic. The bismuth ferrite-based ceramic is a bismuth ferrite-based ceramic material with co-doping at an A position and a B position, the Curie ferroelectric transition temperature TC of the bismuth ferrite-based ceramic material is higher than the Neel temperature TN, and the difference value between the TC and the TN ranges from 10 DEG C to 60 DEG C. The bismuth ferrite-based ceramic is prepared by adopting a standard solid-phase reaction sintering method, and the method comprises the following steps: proportioning raw materials according to a stoichiometric ratio, carrying out primary ball milling, conducting sieving, conducting presintering at 860-880 DEG C to obtain pre-synthesized powder, and carrying out secondary ball milling, sieving, granulating, tabletting and other processes to obtain a BiFeO3-based ceramic green body withexcellent magnetic properties; and finally, conducting sintering at a high temperature of 900-950 DEG C to obtain the BiFeO3-based ceramic material. The preparation method is stable and reliable, theprocess is simple and easy to operate, and large-scale production can be performed; and the bismuth ferrite-based ceramic with uniform components, compact structure and excellent performance can be prepared.

The invention relates to a CoFe2O4/PVDF composite bone scaffold and a preparation method thereof. The CoFe2O4/PVDF composite bone scaffold is prepared by the following steps: mixing and stirring ethanol suspension of CoFe2O4 and ethanol suspension of PVDF, performing solid-liquid phase separation on the obtained CoFe2O4/PVDF mixed suspension, drying and ball-milling the obtained solid phase to obtain composite powder, and performing selective laser sintering on the composite powder. According to the CoFe2O4/PVDF composite bone scaffold provided by the invention, remote non-contact electrical stimulation on bone cells can be realized by externally applying an alternating magnetic field, so that growth of osteoblasts and regeneration and reconstruction of defective tissues are promoted.