Chemical Ordering and Microstructural Affects on Magnetic Properties of Sm2Fe17 and Sm2Fe17Nx

1999 ◽  
Vol 577 ◽  
Author(s):  
B.E. Meacham ◽  
K.W. Dennis ◽  
R.W. Mccallum ◽  
J.E. Shield
Keyword(s):  
Long Range ◽  
Domain Walls ◽  
Antiphase Domain ◽  
Small Degree ◽  
Range Order ◽  
Long Range Order ◽  
Chemical Order ◽  
Chemical Ordering ◽  
Random Anisotropy ◽  
Magnetic Hardness

ABSTRACTThe effect of chemical order and defect structure on the magnetization process in Sm2Fe17 and Sm2Fe17Nx has been investigated. In Sm2Fe17, chemical disorder results in the development of random anisotropy and a small degree of magnetic hardness. The anisotropy is reduced as long-range order increases. The motion of domain walls in Sm2Fe17Nx is more dependent on the antiphase domain structure than on the amount of long-range order.

The Effect of Growth Temperature and Substrate Misorientation on Degree of Order and Antiphase Domain Size in Ga0.52In0.48P Epilayers Grown on GaAs (001) Substrates by Gs-Mbe

1998 ◽  
Vol 523 ◽  
Author(s):  
C. Meenakarn ◽  
A. E. Staton-bevan ◽  
S. P. Najda ◽  
G. Duggan ◽  
A. H. Kean
Keyword(s):  
Band Gap ◽  
Long Range ◽  
Growth Temperature ◽  
Order Parameter ◽  
Plate Thickness ◽  
Antiphase Domain ◽  
Range Order ◽  
Range Order Parameter ◽  
Long Range Order ◽  
Gaas Substrates

AbstractA Transmission Electron Microscopy (TEM), Photoluminescence (PL) and Photoluminescence Excitation Spectroscopy (PLE) investigation has been conducted on Ga0.52In0.48P epilayers grown on (001) GaAs substrates by Gas-Source Molecular Beam Epitaxy.For Ga0.52In0.48P epilayers grown on exact (001) GaAs substrates, increasing the growth temperature from 480°C to 535°C increased the antiphase domain plate thickness, t, from 7.3±0.4 to 17.4±0.9 Å, and decreased the long range order parameter, n, from 0.32 to 0.18±0.1. For epilayers grown at 530°C, on GaAs(001) substrates off-cut 0°, 7°, 10° and 15° towards [111]A, increasing the substrate misorientation from 0° to 15° decreased the antiphase domain plate thickness, from 12.3±0.6 to 6.0±0.3 Å. The long range order parameter also decreased from 0.19 to 0.10±0.01.The band gap energies of these samples, grown by GS-MBE, were close to those reported for fully disordered Ga0.52In0.48P epilayers grown by MOCVD at ∼760°C. This shows that GSMBE is also a good technique to grow GaInP for high band gap optical data storage applications and at lower growth temperatures. The optimum growth conditions in this study were at a growth temperature of 530°C on (001) GaAs substrate with 15° off-cut towards [111]A.

Observation of a Magnetic Antiphase Domain Structure with Long-Range Order in a Synthetic Gd-Y Superlattice

1986 ◽  
Vol 56 (25) ◽  
pp. 2700-2703 ◽  
Author(s):  
C. F. Majkrzak ◽  
J. W. Cable ◽  
J. Kwo ◽  
M. Hong ◽  
D. B. McWhan ◽  
...  
Keyword(s):  
Domain Structure ◽  
Long Range ◽  
Antiphase Domain ◽  
Range Order ◽  
Long Range Order

Observation of a Magnetic Antiphase Domain Structure with Long-Range Order in a Synthetic Gd-Y Superlattice

1986 ◽  
Vol 57 (7) ◽  
pp. 923-923
Author(s):  
C. F. Majkrzak ◽  
J. W. Cable ◽  
J. Kwo ◽  
M. Hong ◽  
D. B. McWhan ◽  
...  
Keyword(s):  
Domain Structure ◽  
Long Range ◽  
Antiphase Domain ◽  
Range Order ◽  
Long Range Order

scholarly journals QUASI-LONG RANGE ORDER IN GLASS STATES OF IMPURE LIQUID CRYSTALS, MAGNETS, AND SUPERCONDUCTORS

2001 ◽  
Vol 15 (22) ◽  
pp. 2945-2976 ◽  
Author(s):  
D. E. FELDMAN
Keyword(s):  
Liquid Crystals ◽  
Long Range ◽  
Disordered Systems ◽  
Critical Dimension ◽  
Range Order ◽  
Long Range Order ◽  
Weak Disorder ◽  
Random Anisotropy ◽  
Ordered Phases ◽  
Amorphous Magnets

We consider glass states of several disordered systems: vortices in impure superconductors, amorphous magnets, and nematic liquid crystals in random porous media. All these systems can be described by the random-field or random-anisotropy O(N) model. Even arbitrarily weak disorder destroys long range order in the O(N) model. We demonstrate that at weak disorder and low temperatures quasi-long range order emerges. In quasi-long-range-ordered phases the correlation length is infinite and correlation functions obey power dependencies on the distance. In pure systems quasi-long range order is possible only in the lower critical dimension and only in the case of Abelian symmetry. In the presence of disorder this type of ordering turns out to be more common. It exists in a range of dimensions and is not prohibited by non-Abelian symmetries.

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