Effects of Heat Treatment on the Phase Evolution, Structural, and Magnetic Properties of Mo-Zn Doped M-Type Hexaferrites

In this article we report on the structural and magnetic properties of BaFe12-4xMoxZn3xO19hexaferrites with Mo-Zn substitution for Fe ions. The starting materials were commensurate with the BaM stoichiometry, and the Mo:Zn ratio was 1:3. The powder precursors were prepared by high energy ball milling, and subsequently sintered at temperatures from 1100 to 1300° C. The structural analyses indicated that all samples sintered at 1100° C were dominated by a major M-type hexaferrite phase. The relative abundance of the BaMoO4and Zn-spinel secondary phases increased with increasing the concentration of the substituents, resulting in a decrease of the saturation magnetization from about 67 emu/g (forx= 0.0) to 55 emu/g (forx= 0.3). The coercivity also decreased from 3275 Oe (forx= 0.0) to 900 Oe (forx= 0.3), demonstrating the ability to tune the coercivity to the range useful for magnetic recording by the substitution process. The saturation magnetization improved significantly with sintering atT> 1100° C, and the coercivity decreased significantly, signaling the transformation of the samples to soft magnetic materials. These magnetic changes were due to the high-temperature reaction of the spinel phase with the BaM phase to produce the W-type hexaferrite phase on the one hand, and to the growth of the particles on the other hand. The magnetic phases were further investigated using Mössbauer spectroscopy and thermomagnetic measurements. Our study indicated that the sample withx= 0.2 has the highest saturation magnetization (74 emu/g at sintering temperature of 1300° C) and a tunable coercivity between 2100 Oe and 450 Oe.

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Microstructural and Magnetic Behavior of Nanocrystalline Fe-12Ni-16B-2Si Alloy Synthesis and Characterization

Metals ◽

10.3390/met11111679 ◽

2021 ◽

Vol 11 (11) ◽

pp. 1679

Author(s):

Kaouther Zaara ◽

Mohamed Khitouni ◽

Lluisa Escoda ◽

Joan Saurina ◽

Joan-Josep Suñol ◽

...

Keyword(s):

Solid Solution ◽

Magnetic Properties ◽

Saturation Magnetization ◽

Milling Time ◽

Milled Powder ◽

Magnetic Behavior ◽

Phase Evolution ◽

High Energy ◽

Refined Microstructure ◽

Hard Magnetic Properties

The nanocrystalline Fe70Ni12B16Si2 (at.%) alloy was prepared by mechanical alloying (MA) of elemental powders in a high-energy planetary ball mill. Phase evolution, microstructure, thermal behavior and magnetic properties were investigated. It was found that a body-centered cubic structured solid solution started to form after 25 h milling and a faced-centered cubic structure solid solution started to form after 50 h of milling; its amount increased gradually with increasing milling time. The BCC and the FCC phases coexisted after 150 h of milling, with a refined microstructure of 13 nm and a 10 nm crystallite size. The as-milled powder was annealed at 450 °C and 650 °C and then investigated by vibrating sample magnetometry (VSM). It was shown that the semi-hard magnetic properties are affected by the phase transformation on annealing. The saturation magnetization decreases after annealing at 450 °C, whereas annealing at 650 °C improves the magnetic properties of 150 h milled powders through the reduction of coercivity from 109 Oe to 70 Oe and the increase in saturation magnetization.

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CVD of CrO2 Thin Films: Influence of the Deposition Parameters on their Structural and Magnetic Properties

Materials Science Forum ◽

10.4028/www.scientific.net/msf.514-516.284 ◽

2006 ◽

Vol 514-516 ◽

pp. 284-288 ◽

Cited By ~ 1

Author(s):

Ana F.S. Mota de Oliveira ◽

António J. Silvestre ◽

Pedro M. Sousa ◽

Olinda Conde ◽

M. Alexandra Rosa ◽

...

Keyword(s):

Thin Films ◽

Magnetic Properties ◽

Saturation Magnetization ◽

Atmospheric Pressure ◽

Chromium Trioxide ◽

Magnetic Transition ◽

Deposition Parameters ◽

Structural And Magnetic Properties

This work reports on the synthesis of CrO2 thin films by atmospheric pressure CVD using chromium trioxide (CrO3) and oxygen. Highly oriented (100) CrO2 films containing highly oriented (0001) Cr2O3 were grown onto Al2O3(0001) substrates. Films display a sharp magnetic transition at 375 K and a saturation magnetization of 1.92 µB/f.u., close to the bulk value of 2 µB/f.u. for the CrO2.

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Effect of Ball Milling on Magnetic Properties of Nb Substituted R2Fe16Nb1 (R: Gd and Er) Alloys

MRS Proceedings ◽

10.1557/opl.2013.392 ◽

2013 ◽

Vol 1516 ◽

pp. 227-231

Author(s):

B. K. Rai ◽

S. R. Mishra ◽

S. Khanra ◽

K. Ghosh

Keyword(s):

Magnetic Properties ◽

Curie Temperature ◽

Saturation Magnetization ◽

Ball Milling ◽

Grain Refinement ◽

High Energy ◽

High Energy Ball Milling ◽

Lattice Expansion ◽

Energy Ball

AbstractIn this work, we report the effect of high energy ball milling (HEBM) on Nb doped R2Fe16Nb1 (R= Gd, Er) compounds. The focus of the work is to bring enhancement in magnetic properties of R2Fe17 (2:17) compounds with the ball milling. Specifically, we find that the ball milling increases saturation magnetization, coercivity, and Curie temperature. The increase in the magnetization and Curie temperature upon ball milling is related to the lattice expansion and microstrains while the increase in coercivity is related to the grain refinement.

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Microstructure and Magnetic Properties of Rapidly Solidified Sm(CobalFe0.11Cu0.10Zrx)7 Alloys

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.893.357 ◽

2014 ◽

Vol 893 ◽

pp. 357-360

Author(s):

Li Ya Li ◽

Yi Cheng Ge ◽

Yuan Dong Peng

Keyword(s):

Magnetic Properties ◽

Saturation Magnetization ◽

Systematic Study ◽

Structure Type ◽

Zr Addition ◽

Heat Treated ◽

Intrinsic Coercivity ◽

Structural And Magnetic Properties ◽

Rapidly Solidified ◽

Microstructure And Magnetic Properties

We reported a systematic study of the effect of Zr content on the structural and magnetic properties of rapidly quenched Sm (CobalFe0.11Cu0.10Zrx)7 alloys with x varying from 0 to 0.04. The results show that the addition of Zr greatly affected the microstructure and magnetic properties of the heat-treated ribbons. The Zr-free ribbon had crystallized as the 1:7H structure as the main phase while the ribbon with Zr addition adopted the 2:17R structure type. A Sm2Co7 phase was observed in the heat-treated ribbons when the Zr content x increased to 0.04. It is found that while the Zr content was increased from 0 to 0.04, saturation magnetization of the heat-treated ribbons was decreased from 11.9kGs to 3.3 kGs, and the intrinsic coercivity was increased from 0.07 kOe to 11.7 kOe. The highest intrinsic coercivity, Hci=11.7 kOe, was obtained in the ribbon with Zr content of 0.03.

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Magnetic Properties of FePt Nanoparticles Prepared by Sonoelectrodeposition

Journal of Nanomaterials ◽

10.1155/2012/801240 ◽

2012 ◽

Vol 2012 ◽

pp. 1-4 ◽

Cited By ~ 7

Author(s):

Nguyen Hoang Nam ◽

Nguyen Thi Thanh Van ◽

Nguyen Dang Phu ◽

Tran Thi Hong ◽

Nguyen Hoang Hai ◽

...

Keyword(s):

Magnetic Properties ◽

Saturation Magnetization ◽

Metallic Nanoparticles ◽

Room Temperature ◽

Cathode Surface ◽

High Coercivity ◽

Fept Nanoparticles ◽

Promising Technique ◽

Structural And Magnetic Properties

Sonoelectrodeposition is a useful technique to make metallic nanoparticles, using ultrasound during electrodeposition to remove nanoparticles as they grow on the cathode surface. This paper reports some structural and magnetic properties of FePt nanoparticles prepared by this method. The as-prepared Fe45Pt55nanoparticles were ferromagnetic at room temperature. Upon annealing at 700°C for 1 h under H2atmosphere, the saturation magnetization and the coercivity of the nanoparticles were improved significantly. The annealed nanoparticles showed a high coercivity of 13.5 kOe at 2 K and of 9 kOe at room temperature. Sonoelectrodeposition is a promising technique to make large quantity of FePt nanoparticles.

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Structural and Magnetic Properties of Ba3[Cu0.8−xZnxMn0.2]2Fe24O41 Z-Type Hexaferrites

Advances in Materials Science and Engineering ◽

10.1155/2018/6152020 ◽

2018 ◽

Vol 2018 ◽

pp. 1-11

Author(s):

Eman S. Al-Hwaitat ◽

Sami H. Mahmood ◽

Mahmoud Al–Hussein ◽

Ibrahim Bsoul

Keyword(s):

Magnetic Properties ◽

Anisotropy Field ◽

High Energy ◽

X Ray Diffraction ◽

Zn Content ◽

Energy Ball ◽

Structural And Magnetic Properties ◽

Ball Milling Technique ◽

Xrd Patterns

We report on the synthesis and characterization of Ba3[Cu0.8−xZnxMn0.2]2Fe24O41 (x = 0.0, 0.2, 0.4, 0.6, and 0.8) barium hexaferrites. The samples were prepared by high-energy ball-milling technique and double-sintering approach. The effects of Zn substitution for Cu on the structural and magnetic properties of the prepared samples were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM). XRD patterns of the samples revealed the presence of a major Z-type hexaferrite phase, together with secondary M-type and Y-type phases. The magnetic results indicated that the saturation magnetization increased slightly with increasing the Zn content, while the coercivity and magnetocrystalline anisotropy field exhibited a decreasing tendency with the increase of Zn content. The thermomagnetic curves revealed the complex magnetic structure of the prepared samples and confirmed that the Curie temperature of the magnetic phases decreased with increasing x as a result of the reduction of the strength of the superexchange interactions.

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Effect of La3+ Substitution on the Structural and Magnetic Properties of Mn-Zn Ferrite Prepared by Sol-Gel Auto-Combustion Method

Materials Science Forum ◽

10.4028/www.scientific.net/msf.916.91 ◽

2018 ◽

Vol 916 ◽

pp. 91-95

Author(s):

Beh Hoe Guan ◽

Muhammad Hanif bin Zahari ◽

Kean Chuan Lee

Keyword(s):

Magnetic Properties ◽

Rare Earth ◽

Spinel Ferrite ◽

Sol Gel ◽

Combustion Method ◽

Secondary Phases ◽

Zn Ferrite ◽

Auto Combustion ◽

Structural And Magnetic Properties ◽

The Rare Earth

Spinel ferrite with the chemical formula of Mn0.5Zn0.5LaxFe2-xO4(x= 0.02, 0.04, 0.06, 0.08, 0.10) were prepared by a sol-gel auto-combustion method. The effect of the rare-earth substitution on the microstructural properties of the synthesized powders were investigated through X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM), while for the magnetic properties, vibrating sample magnetometer (VSM) measurements were made. XRD patterns revealed characteristic peaks corresponding to spinel Mn-Zn ferrite structures with accompanying secondary phases, such as Fe2O3and LaFeO3. The initial addition of La3+into the spinel ferrite system resulted in an initial spike of the lattice parameter and crystallite size before proceeding to decrease as the rare-earth content continues to decrease. FESEM micrographs reveals agglomerated particles with considerable grain size distribution. The magnetic properties, especially the saturation magnetization,Ms, was found to decrease with each increase in La3+substitution. The research findings revealed the critical influence of the La3+substitution towards the overall structural and magnetic properties of the Mn-Zn ferrite samples.

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