117 results about "Magnetic phase" patented technology

Apparatus and methods are described including a ventricular assist device that includes an impeller configured to be placed inside a left ventricle of a subject. A driving magnet is coupled to a motor and is rotated by the motor. A driven magnet is magnetically coupled to the driving magnet and is rotated by the driving magnet. A drive cable extends from the driven magnet and imparts rotational motion from the driven magnet to the impeller. A set of sensors is configured to detect a magnetic phase difference between the driven magnet and the driving magnet. A computer processor receives the detected magnetic phase difference and determines a physiological parameter of the subject, at least partially in response thereto. Other applications are also described.

The invention provides a magnetic code disc film material and a preparation method and application thereof. By introducing the TiN layer, a proper amount of nitrogen atoms can enter lattice gaps of iron, electron cloud distribution of iron atoms is changed, and the magnetic moment of the iron atoms is changed; the magnetic moment of Fe atoms can be influenced by N atoms and crystal structures, an alpha-Fe8N phase is formed in FeCoCr through introduction of N ions, the average magnetic moment of each Fe atom in the alpha-Fe8N phase is 2.4 mu B, alpha-Fe8N is a metastable phase, a sample can finally form stable gamma '-Fe4N through annealing, and the magnetic moment of the stable gamma'-Fe4N is generally about 2.5 mu B-2. 7 mu B and is higher than the magnetic moment 2.2 mu B of the Fe atoms in metal Fe; besides, Ti forms a Ti-Fe weak magnetic phase pinning magnetic domain wall in the FeCoCr thin film, and the coercive force and residual magnetism of the FeCoCr layer can be effectively improved at the same time through the method.

The invention discloses a preparation method of a high-frequency and high-stability carbonyl ferromagnetic powder core, and belongs to the field of magnetic functional materials. On the basis of organic and inorganic composite coating, a uniform and high-resistance SiO2 insulating coating layer is formed on the surface of carbonyl iron particles by adopting a simplified insulating coating process, and the process does not need to adopt a silane coupling agent to perform surface modification on carbonyl iron powder so as to control the thickness of the SiO2 coating layer within a reasonable interval; weakening of the magnetic performance of the magnetic powder core caused by introduction of the non-magnetic phase is reduced to the maximum extent; the formed magnetic powder core does not need to be subjected to heat treatment, the onion layered special structure of the carbonyl iron powder particles is prevented from being damaged, the preparation process is simplified, operability is high, and the raw material cost is low. According to the preparation method, the bulk resistivity of the material is greatly improved, the magnetic core loss under the high-frequency condition is reduced, the quality factor, the direct-current anti-saturation characteristic, the magnetic conductivity temperature coefficient and the magnetic conductivity frequency change rate of the carbonyl ferromagnetic powder core are optimized, and the prepared magnetic powder core obtains high stability within the high-frequency range of 1-40 MHz.

The invention discloses a method for predicting the room-temperature magnetic performance of a neodymium iron boron permanent magnet, which is a prediction method based on practice and theoretical analysis, the prediction method deforms an existing residual magnetism and coercive force theoretical formula, and the form is changed into a form containing phase composition parameters based on actual deformation from a theoretical aesthetic form. According to the prediction method, a residual magnetism and coercive force calculation model is established by calculating the proportion of the main phase (NdFeB) to the non-magnetic phase (Non-magnetic Phase), simple, efficient and accurate prediction of the room-temperature magnetic performance of the neodymium-iron-boron permanent magnet is achieved, the non-magnetic phase composition and components which cannot be quantitatively analyzed can be bypassed, and the prediction accuracy of the room-temperature magnetic performance of the neodymium-iron-boron permanent magnet is improved. The influence of the components of the neodymium-iron-boron permanent magnet on the performance is simply and clearly displayed and calculated from a more macroscopic perspective, and a universal and quantitative rapid solution can be provided for component design and process design of various neodymium-iron-boron permanent magnets.

The invention relates to a cerium-iron-boron permanent magnet material with low content of a non-magnetic phase CeFe2 and a preparation method of the cerium-iron-boron permanent magnet material. The cerium-iron-boron permanent magnet material is composed of the following components in percentage by atom: 11%-17% of Ce, 70%-80% of Fe, 5%-10% of B, 0.1%-3% of Co, 0.1%-3% of Zr and 0.1%-5% of La. The preparation method comprises the following steps of S1, smelting, wherein Ce, La, Fe, Co, Zr and FeB are prepared into a CeLaFeCoZrB alloy cast ingot through electric arc smelting according to the atomic percent composition; s2, melt-spinning: crushing the CeLaFeCoZrB alloy ingot prepared in the S1, and then preparing an alloy strip by using a melt rapid quenching method; and S3, magnetic field annealing: performing vacuum annealing on the alloy strip prepared in S2, wherein the annealing temperature is 2-12K below the Curie temperature Tc of the alloy. Compared with the prior art, the method has the advantages that the phase volume fraction of the non-magnetic CeFe2 phase in the cerium-iron-boron permanent magnet material alloy is remarkably reduced, and the residual magnetism and the maximum magnetic energy product of the alloy are improved.

The invention discloses an all-component comprehensive utilization method for limonite type laterite-nickel ore, and belongs to the technical field of mineral processing and metallurgy. According to the method, multi-stage preheating and selective reduction are combined, accurate regulation and control of ore phase conversion are achieved by optimizing temperature and atmosphere conditions, metallic nickel and cobalt generated through reduction form a stable complex in the ammonia leaching process, and magnetite serves as an indissolvable magnetic phase to be left in slag. The reaction temperature is effectively reduced, the energy consumption is reduced, and the gas-solid mass transfer efficiency and the heat transfer efficiency are remarkably improved. The mineral structure is regulated and controlled through selective reduction, the adverse effects of excessive reduction, sintering, follow-up leaching difficulty and the like of iron oxide in the high-temperature roasting process of a traditional rotary kiln are avoided, and efficient selective leaching of nickel and cobalt and recovery and enrichment of magnetic iron ore are achieved. And meanwhile, the nickel and cobalt leaching efficiency is remarkably improved, interference of iron impurities on a leaching solution is reduced, and an economical and feasible new technical path is provided for resource comprehensive utilization and green metallurgy development of the limonite type laterite-nickel ore.

The invention discloses a method for regulating and controlling magnetic anisotropy of a Cr-based MXene material through charges. The method comprises the following steps: synthesizing an MAX precursor; the MAX precursor is subjected to etching and stripping, and a single-layer Cr-based MXene nanosheet is obtained; on the basis of a single-layer Cr-based MXene nanosheet, a substrate, an electrode and ionic liquid are used for synthesizing and regulating a Cr-based MXene material charge-doped ionic liquid gate structure. The method has the remarkable effects that the magnetic anisotropy (MAE) of the Cr2TiC2O2 material is improved through charge doping, the magnetic easy axis direction is regulated and controlled, the magnetism and the magnetic phase change can be accurately regulated, the magnetic order temperature of the material is remarkably improved, and the application potential of the material in a high-temperature environment is widened.

The invention discloses a FeNi soft magnetic composite material based on tetrabutyl orthosilicate hydrolysis coating and a preparation method of the FeNi soft magnetic composite material. According to the method, through a controllable sol-gel process, tetrabutyl orthosilicate is hydrolyzed to generate SiO2 gel, then a uniform and ultrathin SiO2 gel layer is generated on the surface of FeNi powder in situ, and then heat treatment densification is performed to obtain the FeNi soft magnetic composite material coated with SiO2 in an insulation mode. The SiO2 insulating layer is firmly combined with the matrix metal powder, the thermal stability is good, high frequency and high resistivity are achieved, and meanwhile dilution of non-magnetic relative magnetic performance is reduced to a great extent. The final magnetic core is obtained through compression molding and annealing heat treatment, has the excellent characteristics of high effective magnetic conductivity and low high-frequency magnetic core loss, and is particularly suitable for various efficient and miniaturized power electronic devices in the MHz frequency band.

The application discloses a micro patch power inductor based on micro area 3D printing and a preparation method thereof, and belongs to the technical field of 3D printing micro inductor devices. The preparation method uses Fe-based soft magnetic powder as a magnetic phase raw material to prepare a 3D printing support medium; a micro area 3D printing method is used to print at least one group of coils and lead-out ends of the coils in the support medium, so that the coils and the lead-out ends are completely embedded in the support medium, and an inductor blank is formed; after the support medium and the inductor blank are separated, the inductor is prepared, the inductor is cleaned and silver-plated; the inductor after silver-plating is annealed, and a micro patch power inductor is prepared. The method can print micron-level coils, the prepared inductor has a smaller volume, can reach a wire diameter of 10 um, has a good yield, can be annealed, the magnetic permeability of the magnetic material is improved, the magnetic hysteresis loss is reduced, and the prepared inductor has higher electromagnetic performance under the same volume condition.

The present invention discloses a method for preparing high-performance composite magnetic powder, which belongs to the field of magnetic material technology. The preparation method comprises: firstly preparing Sm2Fe 17 The invention relates to a method for preparing a magnetic particle and nitriding it to obtain a samarium iron nitrogen particle magnet; and during the high-energy ball milling process of metal Sm and metal Co, a mixture of the samarium iron nitrogen particle magnet and gasoline is sprayed into a mixed powder of metal Sm and metal Co in a spray manner, so that Sm and Co react chemically to achieve the synthesis of a hard magnetic phase Sm-Co phase, simplifying the preparation process, eliminating the smelting process, and avoiding the volatilization of Sm; finally, the magnetic mixed powder is subjected to a primary and secondary laser fast sintering nitriding and tempering heat treatment in a nitrogen atmosphere to finally obtain a high-performance composite magnetic powder. The method of the present invention has a simple process, is easy to form, reduces costs, and is conducive to the application of high-performance magnets in more permanent magnet devices.

The invention relates to temperature-control concrete for regulating and controlling distribution of phase-change lightweight aggregate based on a magnetic field and a preparation method thereof. The concrete comprises the following components in percentage by mass (kg / m < 3 >): 730-870% of magnetic phase-change lightweight aggregate; 240 to 380 parts of shale pottery sand; 450 to 550 parts of cement; 40-60 parts of silica fume; 0-30 parts of fly ash; 5-7 parts of a water reducing agent; 0 to 61.4 parts of floating beads; 20 to 15 parts of nano SiO; 50 to 80 parts of water; and 1.5 to 7.5 parts of carbon fiber. The preparation method comprises the following steps: 1, designing a magnetic field device to cover the whole concrete pouring area; 2, mixing the six magnetic phase change aggregates; 3, the shale pottery sand is pre-wetted to a saturated surface dry state; 4, uniformly stirring the silica fume, the cement, the fly ash, the floating beads and the nano SiO2; 5, adding the rest components in two batches; sixthly, stirring the concrete, pouring the concrete into the mold, and starting the magnetic field device at the same time; and 8, after initial setting of the concrete, closing the magnetic field device and maintaining.

The invention belongs to the technical field of permanent magnet materials, and relates to a nanocrystalline composite permanent magnet material and a manufacturing method thereof. The nanocrystalline composite permanent magnet material comprises a hard magnetic phase and a soft magnetic phase, the grain size of the hard magnetic phase and the grain size of the soft magnetic phase are independently smaller than or equal to 25 nm; the content of the soft magnetic phase is greater than 40 wt.%; the hard magnetic phase comprises a hard magnetic main phase, the proportion of the hard magnetic main phase in the hard magnetic phase is larger than 50 wt.%, and the hard magnetic main phase is a rare earth cobalt-based hard magnetic phase. The maximum magnetic energy product of the nanocrystalline composite permanent magnet material obviously exceeds the theoretical upper limit of the magnetic energy product of the single-phase hard magnetic material of the hard magnetic main phase. The giant magnetic energy product effect of the nanocrystalline composite permanent magnet material is realized by strictly controlling the raw material ratio and the preparation process.

A device and method for high speed metamagnetic resistive switching provides a metamagnetic phase transitioning (MPT) portion formed on a substrate between terminals. The MPT portion is tuned for temperature-responsive transitions between magnetic phases through a transition phase. The phases are delineated by phase boundaries each traversed at different critical temperatures depending on direction of traversal. The critical temperatures of each phase boundary are mutually offset by a hysteretic shift. The MPT portion is boosted across one phase boundary responsive to thermal actuation pulsed in a first direction to reach or exceed both critical temperatures of that phase boundary in the first direction, and boosted across the other phase boundary responsive to thermal actuation pulsed in a second direction to reach or exceed both critical temperatures of that phase boundary in the second direction. The electrical conduction path is thereby adjusted in resistivity for switching between ON and OFF states.

The present disclosure relates to an anisotropic bulk magnet and a method for manufacturing the same. The anisotropic bulk magnet has a high fraction of a (Re,Ce)2(Fe,Ti)14B phase (magnetic phase), a low fraction of a (Re,Ce)Fe2 phase (non-magnetic phase), a fine crystal grain size, an excellent degree of crystal grain alignment, and a high rare earth element content at an interface of the crystal grain, and therefore, may have excellent magnetic properties such as coercivity and maximum magnetic energy product.

A multilayer coil component includes a multilayer body in which a plurality of insulating layers are stacked in a stacking direction and a coil inside, and outer electrodes on surfaces of the multilayer body and electrically connected to the coil. The insulating layers have a magnetic phase having spinel structure containing at least Fe, Ni, Zn, and Cu and a non-magnetic phase containing at least Si. When grain sizes D50 and D90 of crystal grains constituting the magnetic phase are respectively defined as equivalent-area circle diameters of 50% and 90% on a cumulative sum basis in a cumulative distribution of equivalent-area circle diameters of the crystal grains, the grain size D50 is from 50 nm to 750 nm, and the grain size D90 is from 200 nm to 1500 nm.

A rare-earth permanent magnet powder, wherein the rare-earth permanent magnet powder comprises 4 to 12 atomic% Nd, 0.1 to 2 atomic% C, 10 to 25 atomic% N and 62.2 to 85.9 atomic% T, wherein the T is Fe or FeCo and the main phase of the rare-earth permanent magnet powder is a hard magnetic phase with a TbCu7 structure; wherein the rare-earth permanent magnet powder further comprises 1 to 5 atomic% of element A and 0.1 to 2 atomic% of element boron; where the element A is Zr and / or Hf, the ratio of the content of the element boron to the content of the element A is 0.1 to 0.5; where the content of the element Nd and the element A in the rare-earth permanent magnet powder is 4 to 12 atomic % of the total content of the rare-earth permanent magnet powder, and the ratio of the content of the element C to the sum of the content of the element Nd and the element A in the rare-earth permanent magnet powder is 0.05 to 0.12.

The invention provides a biphase composite magnetic material design calculation method and device, equipment and a medium, and relates to the technical field of magnetic materials. The method comprises the following steps: respectively carrying out structure optimization on single-phase unit cells of a soft magnetic phase and a hard magnetic phase to obtain a stable single-phase unit cell structure; combining a soft magnetic phase and a hard magnetic phase based on magnetic performance analysis of a single-phase unit cell structure; and in consideration of atomic bonding, lattice mismatch and orbital hybridization, calculation parameters are set to execute atomic relaxation, and the energy-stable combined unit cell model of the biphase composite magnetic material is obtained. On the basis of the density functional theory, the influence of the interfacial effect and different soft and hard magnetic phase thickness ratios on the magnetic performance in the double-phase composite magnetic material is researched, so that the screening and design process of a novel magnetic material meeting specific function requirements can be remarkably accelerated; and a powerful theoretical basis and a material basis are provided for developing next-generation energy-saving and reliable power electronic equipment.

The production method of a rare earth magnet of the present disclosure includes a coated magnetic powder preparation step, a mixed powder preparation step, and a pressure sintering step. In the coated magnetic preparation step, a zinc-containing coating 12 is formed on the particle surface of a samarium-iron-nitrogen-based magnetic powder to obtain a coated magnetic powder 14. In the mixed powder preparation step, a binder powder 20 having a melting point not higher than the melting point of the coating 12 and the coated magnetic powder 14 are mixed to obtain a mixed powder. In the pressure sintering step, denoting as T1° C. the temperature at which the peak disappears in an X-ray diffraction pattern of the binder powder 20 and as T2° C. the temperature at which the magnetic phase in the samarium-iron-nitrogen-based magnetic powder 10 decomposes, the mixed powder is pressure-sintered at T1° C. or more and (T2−50° C.) or less.

An embodiment of the present invention provides a magnetically controlled phase change heat storage device and method, wherein the device includes a tank body, a heat transfer mechanism, a temperature sensor, a magnetic field generator and a controller; the tank body is filled with a magnetic phase change material; the heat transfer mechanism partially passes through the tank body; the temperature sensor is arranged in the tank body; the temperature sensor and the magnetic field generator are both connected to the controller, and the controller is used to control the magnetic field generated by the magnetic field generator according to the temperature value inside the tank body measured by the temperature sensor, so that the magnetic field magnetizes the magnetic phase change material to form a thermomagnetic convection effect, causing the magnetic phase change material to undergo phase change to store or release energy, thereby regulating the temperature inside the tank body; the heat energy storage or release process can be accelerated or decelerated according to the instantaneous temperature difference, so that the phase change energy storage has adaptive active controllability, thereby expanding the range of applicable working conditions.

The invention concerns a method for manufacturing a magnet from recycled magnets comprising the following steps of:providing:a 1st powder comprising grains of a magnetic phase TR2Fe14B, metal-based compounds and a grain boundary phase rich in rare earth, said 1st powder being free of heavy rare earth,a 2nd powder obtained from recycled magnets comprising heavy rare earths,the 2nd powder is subjected to a hydrogenation-disproportionation treatment,the 1st powder is mixed with the 2nd powder obtained at the end of step b),the mixture obtained at the end of step c) is subjected to a compacting step so as to obtain a compacted part,the compacted part obtained at the end of step d) is subjected to a sintering step so as to obtain a magnet.

The invention discloses a lightweight concrete wave-absorbing material based on a carbon-based magnetic material and a preparation method of the lightweight concrete wave-absorbing material, and relates to the technical field of lightweight building materials.Natural plant fibers are used for replacing materials such as conductive carbon black, graphene and carbon nanotubes in a traditional carbon-based magnetic material, and after high-voltage electricity is used for instantaneous carbonization, the carbon-based magnetic material is prepared into the lightweight concrete wave-absorbing material based on the carbon-based magnetic material. Natural plant fibers form carbonized fiber veins, the conductive wave-absorbing performance of the carbonized fiber veins is similar to that of a traditional carbon material, the whole conductivity of the carbonized fiber veins is far higher than that of the traditional carbon material due to the fact that the plant fibers are long and good in crosslinking performance, and a large number of originally non-contact fiber veins are broken down and communicated due to the action of current. Meanwhile, a magnetic phase attached to the surface of the plant fiber can be melted due to current and fused with a carbonized fiber vein, so that the electrical conductivity and the magnetic conductivity of the material are further improved, the electrical loss and the magnetic loss of the material to electromagnetic waves are increased, the wave absorbing performance of the material is improved, and the production cost is reduced.

The application discloses a kind of full material state multi-field coupling magnetic phase change regulation and control method and application system, it is related to magnetic phase change technical field, it solves the technical problem that existing technology exists excitation source single and material state range narrow, including the following steps: step 1, based on the determination rule of excitation source, at least one of magnetic field, electric field, temperature field, stress field is selected to constitute the excitation source, and the interaction of the excitation source and the electron spin or magnetic moment of substance occurs and changes system free energy;Established the unified regulation and control method covering multiple excitation sources, multiple material states, solved the technical problems that existing technology excitation source is single, material state range is narrow;Provide specific material system and implementation mode, cover solid alloy, liquid magnetorheological fluid, soft matter hydrogel, high-entropy alloy and multiple material states;Application system integrates memory energy storage and trace displacement driving dual function, can be applied to new energy storage, micro-nano precision manufacturing, aerospace, biological medical treatment and other fields.

The invention provides a composite material and a preparation method thereof, and belongs to the technical field of permanent magnet powder materials. The composite material comprises an inner core, a barrier layer and a functional layer, the surface of the inner core is coated with the barrier layer, the surface of the barrier layer is coated with the functional layer, the inner core is made of permanent magnet powder, the barrier layer is made of at least one metal oxide, and the functional layer is made of at least one of Cu, CuO, AlF3 and MgF2. The surface of the permanent magnet powder is sequentially coated with the barrier layer and the functional layer, the effects of blocking water and oxygen permeation, promoting the subsequent sintering effect and optimizing grain growth and a grain boundary structure can be achieved on the premise that the chemical integrity of a magnetic phase (a main crystal phase) is not sacrificed, and the water and oxygen resistance, the corrosion resistance, the magnetic performance and the dispersity of the composite material can be improved.

The application discloses an iron-based molecular magnetic storage and memory integrated device and belongs to the technical field of semiconductor storage. The device comprises a substrate layer, an FeB molecular magnetic film, a solid-state read-write control layer and a packaging layer. FeB is a unique magnetic phase (atomic ratio 1:1, no impurity phase), and a doping element is connected with FeB units in a molecular bridge to form a molecular-level continuous structure without grains and photolithography. The molar ratio of Fe / B is 85-97% / 3-15%, and the process parameter range is disclosed. The application discloses discarding charge storage, reading and writing data through FeB molecular magnetic moment flip, adapting to three scenes of HDD, SSD and non-volatile memory, having the advantages of low cost, long service life, no data loss after power failure, photolithography exemption and secret storage of core accurate parameters.

The invention relates to the technical field of electronic devices, in particular to an anti-fatigue multi-iron device based on interlayer slippage and a simulation construction method and application thereof. The anti-fatigue multi-iron device comprises a left electrode area, a right electrode area and a center scattering area connected with electrodes at the two ends; the central scattering region comprises a ferroelectric layer and an antiferromagnetic layer, the ferroelectric layer and the antiferromagnetic layer are stacked through Van der Waals force, the ferroelectric layer is of a multi-layer structure, the ferroelectric layer of the central scattering region generates a switchable planar polarization field through interlayer slippage, the magnetic spin direction of the antiferromagnetic layer is turned over, and the magnetic spin direction of the antiferromagnetic layer is turned over. Switching between different magnetic phase states of the magnetic material is achieved, and meanwhile interface defects and wall pinning effects are not generated. The internal planar polarization field of the sliding ferroelectric material enables different anti-ferromagnetic magnetic phases of the sliding ferroelectric material to be switched back and forth, the tunneling barrier height is changed, the tunneling resistance effect is generated, the four-state or even more-state storage capacity can be achieved through coupling among multiple physical fields, and the storage density and energy efficiency are remarkably improved.

The invention provides a ferrite joint and a preparation method thereof, and relates to the technical field of welding, the method comprises the following steps: heating a first raw material to a first target sintering temperature, and carrying out heat preservation for a first time to obtain a first molten glass liquid; after the first molten glass is poured into a first mold, the first molten glass is heated to a first preset temperature, heat preservation is conducted for a first preset time, so that a magnetic phase in the first molten glass is fully separated out, the first molten glass is cooled to the room temperature, magnetic microcrystalline glass brazing filler metal is obtained, and the magnetic microcrystalline glass brazing filler metal is made into a first brazing filler metal sheet; preparing the microcrystalline glass brazing filler metal into a second brazing filler metal sheet; preparing the to-be-connected ferrite assembly, heating the to-be-connected ferrite assembly to a welding temperature, and carrying out heat preservation treatment to obtain a ferrite joint; wherein the welding temperature ranges from 600 DEG C to 700 DEG C. When the magnetic brazing filler metal is used for welding the ferrite, by adopting the preparation method of the ferrite joint, the welding temperature can be reduced, and meanwhile, the strength of the ferrite joint can be ensured.

The application discloses a method for preparing soft-hard magnetic nanometer dual-phase particles by a self-propagating combustion method without external ignition, and comprises the following steps: preparation of soft magnetic phase nanoparticles, formation of a hard magnetic phase surface enrichment layer, self-propagating combustion without external ignition, and heat treatment. By moving the shell layer construction to the precursor stage, the application can reduce free nucleation and macroscopic phase separation, improve interface continuity, and provide a more direct process for the regulation of shell thickness and coverage, thereby providing a new technical path for obtaining soft-hard magnetic nanometer dual-phase particles with a soft magnetic core-hard magnetic shell.

The invention discloses a high intrinsic coercive force permanent magnetic ferrite and a preparation method and application thereof, and belongs to the technical field of permanent magnetic ferrites.The cerium and manganese are introduced in a limited range to partially replace lanthanum and cobalt oxides, Ce can form Ce < 4 + > and Ce < 3 + > more easily, charge offset of Fe < 2 + > and Fe < 3 + > can be compensated, meanwhile, Ce can inhibit overgrowth of crystal grains, Mn adjusts magnetic domain distribution, and therefore the permanent magnetic ferrite with the high intrinsic coercive force can be obtained. The sintering temperature is reduced and ferrite compactness is promoted. In the process of preparing the ferrite, the green body is sintered in a staged gradient heating and cooling mode, through cooling sintering after first heating, overgrowth of crystal grains at a high temperature is inhibited, the crystal grains grow to a reasonable size, and the number of crystal boundaries is controlled, so that magnetic domain migration is hindered, and meanwhile, excessive precipitation of a non-magnetic phase at the crystal boundaries is inhibited; the ferrite can be uniformly heated through rapid cooling, and the uniformity of the grain size is ensured.

The invention belongs to the technical field of soft magnetic high-entropy alloy materials and magnetron sputtering, and particularly relates to a nitrogen-doped high-entropy alloy film inductance material and a preparation method thereof.The high-entropy alloy components comprise B and / or Zr, Fe, Co and Ni elements, and the nitrogen-doped high-entropy alloy film inductance material is obtained through a magnetron sputtering method. The method specifically comprises the steps that in the sputtering process of the high-entropy alloy film, nitrogen with certain partial pressure is introduced, and the nitrogen element is deposited into the high-entropy alloy film and forms nitride with a high-entropy alloy element; the high resistivity characteristic of the material is improved, magnetic performance deterioration caused by introduction of a non-magnetic phase is weakened, meanwhile, the material has excellent magnetic performance, the performance of the film is regulated and controlled by controlling nitrogen partial pressure, nitrides of various different structures are formed, the regulation and control mode is more accurate, the nitrogen doping effect is more uniform, cost is reduced, and the preparation method is suitable for industrial production. The method is suitable for large-scale industrial production.

The invention belongs to the technical field of condensed state physics and material research, and particularly relates to a heavy rare earth transition metal oxide magnetocaloric material screening method which comprises the following steps: obtaining zero field cooling of a test sample and a magnetization intensity-temperature curve of the field cooling, and deriving the magnetization intensity-temperature curve of the field cooling to obtain a magnetic field temperature curve of the field cooling; then the absolute value of the derivative of the field cooling magnetization intensity-temperature curve is obtained, and an absolute value curve is obtained; calculating an average magnetic phase transition temperature based on the absolute value curve; calculating the variance of the absolute value curve at the average magnetic phase transition temperature; calculating the dimensionless variance of the absolute value curve based on the variance of the absolute value curve at the average magnetic phase transition temperature; obtaining an isothermal magnetization curve of the test sample and calculating a magnetic entropy change value; and based on the dimensionless variance value, establishing a quantitative relationship between the magnetic phase change interaction intensity and the magnetic entropy change value, and further screening out a target sample. And theoretical support is provided for development and physical mechanism analysis of the low-temperature heavy rare earth based giant magnetocaloric material.