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Method for magnetic field assisted solvothermal synthesis of ferrite and method for regulating and controlling magnetic grain size and morphological characteristics

A magnetic field-assisted, topographical feature technology, applied in the direction of magnetic materials, magnetic objects, inorganic materials, etc., can solve the problems of high cost and complicated process

Active Publication Date: 2020-10-02
ANHUI UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The disadvantage is that the cost is high and the process is relatively complicated

Method used

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  • Method for magnetic field assisted solvothermal synthesis of ferrite and method for regulating and controlling magnetic grain size and morphological characteristics
  • Method for magnetic field assisted solvothermal synthesis of ferrite and method for regulating and controlling magnetic grain size and morphological characteristics
  • Method for magnetic field assisted solvothermal synthesis of ferrite and method for regulating and controlling magnetic grain size and morphological characteristics

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Experimental program
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Effect test

Embodiment 1

[0045] Please also refer to figure 1 , a method for magnetic field-assisted solvothermal synthesis of ferrite, the steps are as follows:

[0046] ①, solvent pretreatment

[0047] Put oleic acid (OA), oleylamine (OAM) and benzyl ether (BE) into a three-necked flask at a volume ratio of 1:1:4, stir magnetically at 30°C for 0.5h to make the solution evenly mixed, and heat to 120°C Insulate for 0.5h to remove water or alcohol in the solution, and pass high-purity N 2 After protection, heat to 200°C for 1h, and finally heat to 290°C for 0.5h; after the solution is naturally cooled to room temperature, it is used as the preparation of MFe 2 o 4 (M=Co, Ni, Zn) Solvent for ferrite and heat transfer medium.

[0048] ②, using iron and metal M (M = Co, Ni, Zn) acetylacetonate as MFe 2 o 4 (M=Co, Ni, Zn) Raw materials for the preparation of ferrite, weigh the acetylacetonate salt of iron and metal M (M=Co, Ni, Zn) according to the stoichiometric ratio, and mix evenly with the solven...

Embodiment 2

[0056] magnetic field on hard magnetic CoFe 2 o 4 Effect of crystal structure\morphology\magnetic properties

[0057] 1. CoFe 2 o 4 Crystal structure and morphology analysis of

[0058] CoFe synthesized in different magnetic fields 2 o 4 XRD results of samples Co0, Co1, Co2, Co3, Co4 and CoFe 2 o 4 Comparison of standard powder diffraction cards (NO.22-1086) reveals that all samples are single-phase spinel structures with a space group of Fd-3m(227). Figure 5 (a) The XRD patterns of Co0 samples are given only representatively. Figure 5 (b) is the enlarged XRD pattern (open circle) of Co0~Co4 samples around 2θ=35.57°. In order to more clearly determine the 2θ angle corresponding to the diffraction peak, we fit the experimental curve with a Gaussian function (solid line). From Figure 5 From the results of (b), it can be seen that the strongest peak of the Co0 sample is located at the position of 2θ=35.57°; the position of the strongest peak of the sample synthesize...

Embodiment 3

[0073] magnetic field on soft magnetic NiFe 2 o 4 Effect of crystal structure\morphology\magnetic properties

[0074] 1. NiFe 2 o 4 Crystal structure and morphology analysis of

[0075] Figure 10 (a) shows the XRD pattern of Ni0 sample and NiFe 2 o 4 Standard powder diffraction card (NO.54-0964). The position of the strongest peak in the figure is 2θ=35.68°, which corresponds to the diffraction of the (311) crystal plane. By comparison with the standard PDF card, it can be seen that the Ni0 sample is NiFe with a single-phase spinel structure 2 o 4 , the space group is Fd-3m(227).

[0076] Figure 11 SEM (a, d), TEM (b, e) and HRTEM (c, f) images of Ni0 and Ni4 samples are given. From Figure 11(a) It can be seen that the Ni0 sample synthesized without an external magnetic field is mainly composed of spherical particles with non-uniform size, and the diameter of the largest spherical particle is about 1.4 μm. The Ni4 sample synthesized under the condition of an e...

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Abstract

The invention discloses a method for magnetic field assisted solvothermal synthesis of ferrite and a magnetic grain size and morphology characteristic regulation and control method, and belongs to thetechnical field of ferrite preparation and synthesis. The preparation method comprises the following steps of: uniformly mixing oleic acid, oleylamine and dibenzyl ether, heating to remove water or alcohol, and naturally cooling to room temperature; taking iron and acetylacetonate of metal M as raw materials, uniformly mixing the raw materials with a solvent, pouring the mixture into a beaker, putting the beaker into a polytetrafluoroethylene lining of a Hastelloy alloy reaction kettle, and placing a magnet below the beaker in the polytetrafluoroethylene lining; pouring a solvent into the outer side of the polytetrafluoroethylene lining to serve as a heat transfer medium, heating to carry out a solvothermal reaction, thereby obtaining the MFe2O4 ferrite. Through the resistance of the solvent to magnetic ions and particle migration, the dipole interaction force among the magnetic particles and the synergistic effect among the external magnetic field forces, the regulation and control of the size and morphology characteristics of the magnetic crystal grains for preparing the ferrite are realized. By changing the size of the synthetic magnetic field, the magnetic particles with single domain critical size and superparamagnetic critical size can be prepared.

Description

technical field [0001] The invention belongs to MFe 2 o 4 The technical field of ferrite preparation and synthesis, specifically relates to a method for magnetic field-assisted solvothermal synthesis of ferrite and a method for controlling the size and morphology of magnetic grains. Background technique [0002] Magnetic materials are widely used in various fields such as spin-electronic devices, magnetic refrigeration, magnetic storage, and planar quantum Hall effect devices. Magnetic particles and multilayers at the nanoscale exhibit distinctly different properties from bulk materials due to the dramatic impact of size-effect and surface / interface-induced anisotropy on magnetization switching. Specifically, as the particle size decreases to the single-domain critical size, the coercive force (Hc) reaches the maximum; when the particle continues to decrease, the thermal fluctuation (kBT) and the anisotropy energy barrier ΔE=KV (K is The anisotropy constant, V is the part...

Claims

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Application Information

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IPC IPC(8): C01G49/00C01G51/00C01G53/00B82Y40/00H01F1/10H01F1/34H01F41/02
CPCC01G49/0063C01G51/00C01G53/00B82Y40/00H01F1/10H01F1/344H01F41/02C01P2006/42C01P2004/32C01P2004/10C01P2004/61C01P2004/64C01P2004/50C01P2002/32
Inventor 马永青张贤王敏饶瑞
Owner ANHUI UNIVERSITY
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