Magneto-Crystalline Anisotropy Constant in Sm(Co, Cu)5Base Alloy

It is well known that in most rocks the ferromagnetic fraction occurs as small grains dispersed in a solid, magnetically inert matrix. Recently the magnetic anisotropy of rocks and of chondritic meteorites has been subjected to detailed study by the torque-meter method, and, in an attempt to obtain a physical understanding of the shape and crystal alignments of grains which cause magnetic anisotropy in these natural bodies, a number of artificial specimens have been prepared. Iron, nickel, and magnetite powders were mixed into solidifying media and allowed to set in a cylindrical mould in a 10 kilo-oersted field. The torque curves of the resulting specimens reveal a surprising result. It appears that single crystal magnetic grains tend to string together along lines of forc~, thus producing strongly anisotropic specimens, only when the first magneto crystalline anisotropy constant of the ferromagnetic material is positive.

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Structural, Magnetic and Microwave Absorption Characteristics of Ba1-xLaxFe12O19 (x = 0; 0.1; 0.2;0.3;0.5;0.7)

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.855.261 ◽

2020 ◽

Vol 855 ◽

pp. 261-267

Author(s):

Yana Taryana ◽

Ari Adi Wisnu ◽

D. Mahmudin ◽

Yuyu Wahyu ◽

Azwar Manaf

Keyword(s):

Microwave Absorption ◽

Single Phase ◽

Anisotropy Constant ◽

Crystalline Anisotropy ◽

Second Phases ◽

La Substitution ◽

Multi Phase ◽

Magneto Crystalline Anisotropy ◽

Uniform Particle Size ◽

Absorption Characteristics

In this study, effect of La substitution on the microstructure, magnetic properties and microwave absorption characteristics of Ba1-xLaxFe12O19 (x=0, 0.1, 0.2, 0.3, 0.5, 0.7) is reported. The samples were synthesized through mechanical alloying and solid reaction a temperature 1200 °C for 2 hours. A single-phase material occurred only at x = 0 and 0.1. Additional second phases were existing in all samples with x ≥ 0.2 which led to multi-phase materials. The single phase (x = 0 and 0.1) has a relatively uniform particle size distribution with a mean crystallite size 138 nm. Additional phases of respectively Fe2O3 and LaFe2O3 were identified in all samples with x ≥ 0.2. Effect of La substitution is to decrease the magneto crystalline anisotropy constant and the saturation magnetization. The latter is due to a decrease in mass fraction of the main magnetic phase. All Ba1-xLaxFe12O19 samples have superior microwave characteristics which able to absorb more than 99 % the incoming electromagnetic wave entering the material. The absorption bandwidth is found relatively wide within the frequency range 8-12 GHz.

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Extruded Rods with Axial Texture of Polycrystalline Ni-Mn-Ga Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.635.189 ◽

2009 ◽

Vol 635 ◽

pp. 189-194 ◽

Cited By ~ 7

Author(s):

Henryk Morawiec ◽

Józef Lelątko ◽

Tomasz Goryczka ◽

Krystian Prusik ◽

S. Piechota ◽

...

Keyword(s):

Room Temperature ◽

Reduction Rate ◽

Anisotropy Constant ◽

Axial Texture ◽

Crystalline Anisotropy ◽

Columnar Grains ◽

Transient Zone ◽

The Subject ◽

Columnar Grain ◽

Magneto Crystalline Anisotropy

The Ni-Mn-Ga alloys extruded at high temperature with a relatively large reduction rate were the subject of the studies. The microscopic observations of the transient zone in the extruded rods revealed rotation of the columnar grains in the ingot along the rod axis - giving the preferred <001> orientations. Comparison of the texture, magnetization and magneto-crystalline anisotropy constant for samples cut out from the columnar grain zone and these cut from the extruded rods was carried out for two alloys which differ in chemical composition and Ms temperature. Both alloys have the 5M martensitic structure at room temperature. The samples cut out of the ingot and the extruded rods have shown the axial <001> orientation, similar magnetization curves and magnetocrystalline anisotropy constant Ku = 1.5-1.6 J/m3•105.

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Crystal Field Analysis of the Magnetization Curves of HoFe11Ti under High Pressure

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.818.72 ◽

2013 ◽

Vol 818 ◽

pp. 72-76 ◽

Cited By ~ 1

Author(s):

Gang Su

Keyword(s):

High Pressure ◽

Hydrogen Atom ◽

Electric Field ◽

Single Crystals ◽

High Pressures ◽

Field Analysis ◽

Magnetization Curves ◽

Crystalline Electric Field ◽

Crystalline Anisotropy ◽

Magneto Crystalline Anisotropy

The crystalline electric field parameters Anmfor HoFe11Ti under different pressures were evaluated by fitting calculations to the magnetization curves measured on the single crystals at several temperatures. It was found that magneto-crystalline anisotropy has been changed by high pressure and the Anmfor HoFe11Ti under high pressures are strikingly different from Anmfor the corresponding HoFe11Ti H with interstitial hydrogen atom.

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