876results about How to "Low coercivity" patented technology

The magnetic tape has a magnetic layer containing ferromagnetic powder and binder on a nonmagnetic support, wherein the coercive force measured in the longitudinal direction of the magnetic tape is less than or equal to 167 kA/m, a timing-based servo pattern is present on the magnetic layer, and the edge shape specified by observing the timing-based servo pattern with a magnetic force microscope is a shape in which the difference between the value of the 99.9% cumulative distribution function of the width of misalignment from the ideal shape in the longitudinal direction of the magnetic tape and the value L_0.1 of the 0.1% cumulative distribution function, L_99.9-L_0.1, is less than or equal to 180 nm.

A magnetic recording medium includes a substrate, an underlayer, a lower magnetic layer formed on the underlayer, an intermediate layer, and an upper magnetic layer formed on the intermediate layer. The intermediate layer is typically Ru, and promotes antiferromagnetic coupling between the upper and lower magnetic layers. The upper and lower magnetic layers are typically Co alloys. The lower magnetic layer has a high saturation magnetization Ms to promote high exchange coupling between the upper and lower magnetic layers. The dynamic coercivity of the lower magnetic layer is lower than the exchange field to ensure rapid switching of the lower magnetic layer.

A thin-film magnetic head that has a configuration in which the element-formed surface and the opposed-to-medium surface are perpendicular to each other, and a light source is sufficiently distanced from the medium surface is provided. The head comprises at least one near-field-light-generating layer for heating a part of a magnetic medium during write operation by generating a near-field light, having a shape tapered toward a head end surface on the opposed-to-medium surface side, and comprising a near-field-light-generating portion having a light-received surface and a tip reaching the head end surface on the opposed-to-medium surface side, and the light-received surface being sloped in respect to the element-formed surface and being provided in a position where an incident light propagating from a head end surface opposite to the opposed-to-medium surface can reach at least a part of the light-received surface.

The invention relates to a process for separating a dispersed phase from a continuous phase comprising the steps of i) contacting said phases with an effective amount of nanoparticles; ii) applying a magnetic field gradient to the obtained system; iii) separating the obtained phases wherein said nanoparticles are of the core shell type, said core consists of a metal or alloy having soft magnetic properties and said shell contains a graphene layers which are optionally functionalized; to new nanoparticles and method of manufacturing such nanoparticles.

Disclosed herein is an apparatus relating to a magnet member for a dynamoelectric machine comprising, a first portion of the magnet member made of a first magnetic material and a second portion of the magnet member made of a second magnetic material. Further disclosed is a method that relates to increasing performance of an electric machine comprising, determining locations of high demagnetization fields at the dynamoelectric machine, and positioning a magnetic member having a first portion having a higher level of coercivity and a second portion having a lower level of coercivity in the machine such that the portion having a higher level of coercivity is more proximate the location of high demagnetization fields than the portion having the lower level of coercivity.

The invention relates to soft magnetic composite powder and a magnetic powder core preparation method thereof, and belongs to the technical field of powder metallurgy and magnetic materials. According to different magnetic performance characteristics of metal soft magnetic powder, amorphous and nano-crystalline powder and ferrite powder, magnetic performances are linearly calculated and optimally designed, so that the requirements of different magnetic properties are met. Besides, powder sizes are calculated and coordinately designed, the powder is shaped, screened, annealed, coated in an insulated manner and mixed, and the powder with different components is respectively passivated and insulated, weighed according to weight ratio and uniformly mixed to form the composite powder. The prepared soft magnetic composite powder is regular in morphology and good in dispersity and has good apparent density and flowability. In addition, the magnetic performance of a magnetic powder core prepared from the soft magnetic composite powder can be calculated and designed as required, the magnetic powder core has high cost performance and good comprehensive magnetic performance, and the blank of the performance and application of an existing magnetic powder core is effectively filled in.

The invention discloses an iron-based amorphous magnetically soft alloy with uniform element distribution and a preparation method thereof. The expression of the alloy is FeaSibBcPdMe, a, b, c, d and e in the expression represent the atomic percent contents of corresponding components respectively, and meet the following conditions: a is not less than 70 and not greater than 84, b is not less than 2 and not greater than 10, c is not less than 5 and not greater than 18, d is not less than 0.001 and not greater than 8, e is not less than 0.0001 and not greater than 2.5, a+b+c+d+e=100%, and M is one or more of C, N, Sn, Ge, Ga, Al, S, Te, Be, Pb, Mg and Cu. The amorphous strip prepared from the alloy under a high vacuum and argon shield has the characteristic of uniform element distribution, particularly solves the problem of non-uniform distribution of element P in the amorphous alloy, has excellent magnetically soft performance, and is suitable for transformers, engines, power generators, magnetic sensors and the like.

A composite free layer having a FL1/insertion/FL2 configuration where a top surface of FL1 is treated with a weak plasma etch is disclosed for achieving enhanced dR/R while maintaining low RA, and low λ in TMR or GMR sensors. The weak plasma etch removes less than about 0.2 Angstroms of FL1 and is believed to modify surface structure and possibly increase surface energy. FL1 may be CoFe, CoFe/CoFeB, or alloys thereof with Ni, Ta, Mn, Ti, W, Zr, Hf, Tb, or Nb having a (+) λ value. FL2 may be CoFe, NiFe, or alloys thereof having a (−) λ value. The thin insertion layer includes at least one magnetic element such as Co, Fe, and Ni, and at least one non-magnetic element selected from Ta, Ti, W, Zr, Hf, Nb, Mo, V, Cr, or B. When CoFeBTa is selected as insertion layer, the CoFeB:Ta ratio is from 1:1 to 4:1.

A magnet comprising grains of a ferromagnetic material whose main component is iron and a fluorine compound layer or an oxy-fluorine compound layer of fluoride compound particles of alkali metals, alkaline earth metals and rare earth elements, present on the surface of the ferromagnetic material grains, wherein an amount of iron atoms in the fluorine compound particles is 1 to 50 atomic %.

A magnetic powder core comprises a molded article of a mixture of a glassy alloy powder and an insulating material. The glassy alloy comprises Fe and at least one element selected from Al, P, C, Si, and B, and has a texture primarily composed of an amorphous phase. The glassy alloy exhibits a temperature difference ΔT_x, which is represented by the equation ΔT_x=T_x−T_g, of at least 20 K in a supercooled liquid, wherein T_x indicates the crystallization temperature and T_g indicates the glass transition temperature. The magnetic core precursor is produced mixing the glassy alloy powder with the insulating material, compacting the mixture to form a magnetic core precursor, and annealing the magnetic core precursor at a temperature in the range between (T_g−170) K and T_g K to relieve the internal stress of the magnetic core precursor. The glassy alloy exhibits low coercive force and low core loss.

The invention discloses iron-based nanocrystalline soft-magnetic alloy with excellent high-frequency performance and a preparation method thereof. The expression of the alloy is FeaSibPcCuxMy, wherein a, b, c, x and y respectively represent the atomic percent content of corresponding compositions and satisfy the following conditions: 70<=a<=85, 5<=b<=15, 5<=c<=18, 0.0001<=x<=3, 0<=y<=5, a+b+c+x+y=100%, and M is one or more of Zr, Ti, Ta, Hf, Nb, V, W, Mo, Mn, Cr, Re, Zn, In, As, Sb, Bi, Ca, platinum group elements, rare earth elements, N, Sn, Ge, Ga and Al. The alloy is a nanocrystalline soft-magnetic alloy band prepared by employing a single-roller quick-cooling method under the conditions of high vacuum and argon protection. The alloy does not contain B elements, is good in soft magnetic property, high in thermal stability, low in high-frequency loss and low in magnetostriction coefficient.

In a magnet-exciting rotating electric machine system, a rotor surface has magnetic salient poles and island-shaped magnetic poles alternately in circumferential direction, and the island-shaped magnetic poles are constituted so that magnetic flux coming from an external source does not flow through. A magnetic excitation part magnetizes the island-shaped magnetic poles and the magnetic salient poles collectively in the same direction, and then control a flux amount flowing through an armature. The armature has armature coils that face the magnetic salient pole and the island-shaped magnetic pole simultaneously so that driving torque fluctuation or power generation voltage waveform distortion is controlled. The magnetic excitation part changes magnetization state of a field magnet irreversibly, or changes an excitation current to an excitation coil to control a flux crossing the armature.

The invention discloses a Fe-based nanocrystalline soft magnetic alloy with strong amorphous forming ability and a preparing method of the Fe-based nanocrystalline soft magnetic alloy. The alloy has an expression of Fe<x>SiBP<c>Nb<d>Cu<e>, wherein in the expression, each of the x, the a, the b, the c, the d and the e shows the atomic percentage content of the corresponding ingredient, and meets the following conditions that the a is greater than or equal to 0.5 but smaller than or equal to 12; the b is greater than or equal to 0.5 but is smaller than or equal to 15; the c is greater than or equal to 0.5 but smaller than or equal to 12; the d is greater than or equal to 0.1 but smaller than or equal to 3; the e is greater than or equal to 0.1 but smaller than or equal to 3; the x is greater than or equal 70 but smaller than or equal to 85; and the sum of the x, the a, the b, the c, the d and the e is 100 percent. The soft magnetic alloy has the advantages that an ordinary copper mold casting method can be used for preparing a Fe-based amorphous alloy with the critical dimension being 3.5mm; after the annealing; the saturation flux density is greater than 1.5T; and the coercive force value is smaller than 1A/m.