Structural and Magnetic Properties of Mo-Zn Substituted (BaFe12-4xMoxZn3xO19) M-type Hexaferrites

Molybdenum-zinc substituted hexaferrites were synthesized by high-energy ball milling and subsequent sintering at different temperatures (1100, 1200, and 1300° C). The samples sintered at 1100° C exhibited good hard magnetic properties, although a decrease in saturation magnetization from 70.2 emu/g for the unsubstituted sample down to 57 emu/g for the sample with x = 0.3 was observed. The drop in saturation magnetization results mainly from the presence of secondary nonmagnetic oxides. The samples sintered at temperatures ≥1200° C showed an improvement in saturation magnetization, and a sharp drop in coercivith. This behavior was associated with the development of the W-type hexaferrite, the particle growth, and possibly the spin reorientation transition from easy-axis to easy-plane.

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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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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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Effect Of Heat-Treatment On Microstructure And Magnetic Properties Of Nanocrystallized Mn-Zn Ferrite Powders

Archives of Metallurgy and Materials ◽

10.1515/amm-2015-0128 ◽

2015 ◽

Vol 60 (2) ◽

pp. 1347-1350

Author(s):

W.H. Lee ◽

C.S. Hong ◽

S.Y. Chang

Keyword(s):

Heat Treatment ◽

Magnetic Properties ◽

Saturation Magnetization ◽

High Energy ◽

Treatment Temperature ◽

Heat Treated ◽

Zn Ferrite ◽

Energy Ball ◽

Size Of Particles ◽

Increasing Temperature

Abstract The initial ferrite powders were subjected to high energy ball milling at 300rpm for 3h, and subsequently heat-treated at 573-1273K for 1h. Based on the observation of microstructure and measurement of magnetic properties, the heat-treatment effect was investigated. The size of initial powders was approximately 70μm. After milling, the powders with approximately 230nm in size were obtained, which were composed of the nano-sized particles of approximately 15nm in size. The milled powders became larger to approximately 550nm after heat-treatment at 973K. In addition, the size of particles increased to approximately 120nm with increasing temperature up to 973K. The coercivity of initial powders was almost unchanged after milling, whereas the saturation magnetization increased. As the heat-treatment temperature increased, the saturation magnetization gradually increased and the maximum coercivity was obtained at 773K.

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