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Title: Noncollinear phase of TbDy alloys

Abstract

Tb{sub {ital x}}Dy{sub 1{minus}{ital x}} is probably the simplest example of a magnetic system with competing anisotropy. Tb and Dy are both low-temperature easy-plane ferromagnets with well-characterized anisotropy energies, such that Tb moments prefer the {bold b} axis in the hcp structure, while Dy moments prefer the {bold a} axis. It has been predicted, by a two-subnetwork approximation, that the low-temperature phase of the alloys with {ital x} between 0.86 and 0.76 exhibits a nonsymmetry direction of magnetization, a noncollinear spin structure, and 12th-order anisotropy. However, the two-subnetwork approximation is suspect when used to describe magnetic structure in alloys near phase boundaries, such as those between the ferromagnetic and the noncollinear phase. Using a probability distribution for site occupation, we have calculated the fluctuations of the spin orientation and the spin-spin correlation function as a function of composition in the noncollinear phase. The mean-square fluctuation in spin orientation is proportional to ({ital x}{sub {ital b}}{minus}{ital x}){sup 1/2}, where {ital x}{sub {ital b}} is the critical concentration which separates the {bold b} axis ferromagnet from the noncollinear magnet. The average orientation also varies as ({ital x}{sub {ital b}}{minus}{ital x}){sup 1/2}. Therefore, the simple two-subnetwork model is not valid near the phasemore » boundaries. In fact, we find that the fluctuations from the average site occupation increase the range of stability of the noncollinear phase.« less

Authors:
 [1];  [2]
  1. Physics Department, The American University, Washington, DC 20016 (USA)
  2. Solid State Branch (R45), Naval Surface Warfare Center, White Oak, Maryland 20903-5000 (USA)
Publication Date:
OSTI Identifier:
7123536
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics; (USA)
Additional Journal Information:
Journal Volume: 67:9; Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; DYSPROSIUM ALLOYS; MAGNETIC PROPERTIES; TERBIUM ALLOYS; ANISOTROPY; CORRELATIONS; FLUCTUATIONS; QUANTITY RATIO; SPIN; SPIN ORIENTATION; ALLOYS; ANGULAR MOMENTUM; ORIENTATION; PARTICLE PROPERTIES; PHYSICAL PROPERTIES; RARE EARTH ALLOYS; VARIATIONS; 360104* - Metals & Alloys- Physical Properties

Citation Formats

Foster, J J, and Cullen, J R. Noncollinear phase of TbDy alloys. United States: N. p., 1990. Web. doi:10.1063/1.346037.
Foster, J J, & Cullen, J R. Noncollinear phase of TbDy alloys. United States. https://doi.org/10.1063/1.346037
Foster, J J, and Cullen, J R. Tue . "Noncollinear phase of TbDy alloys". United States. https://doi.org/10.1063/1.346037.
@article{osti_7123536,
title = {Noncollinear phase of TbDy alloys},
author = {Foster, J J and Cullen, J R},
abstractNote = {Tb{sub {ital x}}Dy{sub 1{minus}{ital x}} is probably the simplest example of a magnetic system with competing anisotropy. Tb and Dy are both low-temperature easy-plane ferromagnets with well-characterized anisotropy energies, such that Tb moments prefer the {bold b} axis in the hcp structure, while Dy moments prefer the {bold a} axis. It has been predicted, by a two-subnetwork approximation, that the low-temperature phase of the alloys with {ital x} between 0.86 and 0.76 exhibits a nonsymmetry direction of magnetization, a noncollinear spin structure, and 12th-order anisotropy. However, the two-subnetwork approximation is suspect when used to describe magnetic structure in alloys near phase boundaries, such as those between the ferromagnetic and the noncollinear phase. Using a probability distribution for site occupation, we have calculated the fluctuations of the spin orientation and the spin-spin correlation function as a function of composition in the noncollinear phase. The mean-square fluctuation in spin orientation is proportional to ({ital x}{sub {ital b}}{minus}{ital x}){sup 1/2}, where {ital x}{sub {ital b}} is the critical concentration which separates the {bold b} axis ferromagnet from the noncollinear magnet. The average orientation also varies as ({ital x}{sub {ital b}}{minus}{ital x}){sup 1/2}. Therefore, the simple two-subnetwork model is not valid near the phase boundaries. In fact, we find that the fluctuations from the average site occupation increase the range of stability of the noncollinear phase.},
doi = {10.1063/1.346037},
url = {https://www.osti.gov/biblio/7123536}, journal = {Journal of Applied Physics; (USA)},
issn = {0021-8979},
number = ,
volume = 67:9,
place = {United States},
year = {1990},
month = {5}
}