Noncollinear phase of TbDy alloys

doi:https://doi.org/10.1063/1.346037

Title: Noncollinear phase of TbDy alloys

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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 »« less

Authors:

Foster, J J ^[1]; Cullen, J R ^[2]

Physics Department, The American University, Washington, DC 20016 (USA)
Solid State Branch (R45), Naval Surface Warfare Center, White Oak, Maryland 20903-5000 (USA)

Publication Date:: 1990-05-01

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.

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                    Foster, J J, & Cullen, J R. Noncollinear phase of TbDy alloys.  United States.  https://doi.org/10.1063/1.346037

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                    Foster, J J, and Cullen, J R. Tue .  
        "Noncollinear phase of TbDy alloys".  United States.  https://doi.org/10.1063/1.346037.

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@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}

}

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