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Title: Magnetic and magneto-optical properties of rare-earth transition-metal alloys containing Dy, Ho, Fe, Co

Abstract

Amorphous rare-earth transition-metal alloys of composition RE{sub l{minus}{ital x}}TM{sub {ital x}} with RE=Dy, Ho; TM=Fe,Co and 0{lt}{ital x}{lt}1 and Dy{sub l{minus}{ital x}}(Fe,Co){sub {ital x}} were prepared by evaporation. The saturation magnetization, uniaxial anisotropy, coercivity, and Faraday rotation were investigated as a function of composition and temperature. Also, the spectral variation of the Kerr rotation was measured. The magnetization data indicate a strong dispersion of the RE moments due to randomly oriented local crystal field axes. The strong turndown of the Curie temperature for the Fe-rich alloys suggests that an additional dispersion is present in the Fe subnetwork. The mean field theory was used to analyze the temperature variation of the magnetization yielding smaller TM spin values and exchange coupling constants as compared with those of the Gd and Tb analogs. The uniaxial anisotropy constant {ital K}{sub {ital u}} for Dy-Co based alloys was found to vary with the square of the Dy subnetwork magnetization as predicted by the random single-ion theory. The anisotropy of Dy-Fe and Ho based alloys require additionally dipolar terms to account for the measured temperature dependence of {ital K}{sub {ital u}}. The coercive field {ital H}{sub {ital c}} follows a relation {ital H}{sub {ital c}} {similarmore » to} {ital K}{sup 1.5}{sub {ital u}}/{ital M}{sub {ital s}}. The magneto-optical effects are primarily caused by the transition metals and therefore their compositional, temperature, and spectral dependence correspond to that of their Gd and Tb analogs. Optical recording experiments on Dy-FeCo disks yield good write and erase sensitivities and carrier-to-noise ratios up to 60 dB which are comparable to those of GdTb-Fe and Tb-FeCo disks.« less

Authors:
; ; ; ;  [1]
  1. Philips GmbH Forschungslaboratorium Hamburg, Vogt-Koelln-Strasse 30, D-2000 Hamburg 54, Federal Republic of Germany (DE)
Publication Date:
OSTI Identifier:
6260869
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics; (USA)
Additional Journal Information:
Journal Volume: 69:5; Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COBALT ALLOYS; MAGNETIC PROPERTIES; DYSPROSIUM ALLOYS; HOLMIUM ALLOYS; IRON ALLOYS; AMORPHOUS STATE; ANISOTROPY; FARADAY EFFECT; FILMS; MAGNETIC STORAGE DEVICES; MAGNETIZATION; MAGNETO-OPTICAL EFFECTS; MEAN-FIELD THEORY; TEMPERATURE DEPENDENCE; VAPOR DEPOSITED COATINGS; ALLOYS; COATINGS; MEMORY DEVICES; PHYSICAL PROPERTIES; RARE EARTH ALLOYS; 360104* - Metals & Alloys- Physical Properties

Citation Formats

Hansen, P, Klahn, S, Clausen, C, Much, G, and Witter, K. Magnetic and magneto-optical properties of rare-earth transition-metal alloys containing Dy, Ho, Fe, Co. United States: N. p., 1991. Web. doi:10.1063/1.348561.
Hansen, P, Klahn, S, Clausen, C, Much, G, & Witter, K. Magnetic and magneto-optical properties of rare-earth transition-metal alloys containing Dy, Ho, Fe, Co. United States. doi:10.1063/1.348561.
Hansen, P, Klahn, S, Clausen, C, Much, G, and Witter, K. Fri . "Magnetic and magneto-optical properties of rare-earth transition-metal alloys containing Dy, Ho, Fe, Co". United States. doi:10.1063/1.348561.
@article{osti_6260869,
title = {Magnetic and magneto-optical properties of rare-earth transition-metal alloys containing Dy, Ho, Fe, Co},
author = {Hansen, P and Klahn, S and Clausen, C and Much, G and Witter, K},
abstractNote = {Amorphous rare-earth transition-metal alloys of composition RE{sub l{minus}{ital x}}TM{sub {ital x}} with RE=Dy, Ho; TM=Fe,Co and 0{lt}{ital x}{lt}1 and Dy{sub l{minus}{ital x}}(Fe,Co){sub {ital x}} were prepared by evaporation. The saturation magnetization, uniaxial anisotropy, coercivity, and Faraday rotation were investigated as a function of composition and temperature. Also, the spectral variation of the Kerr rotation was measured. The magnetization data indicate a strong dispersion of the RE moments due to randomly oriented local crystal field axes. The strong turndown of the Curie temperature for the Fe-rich alloys suggests that an additional dispersion is present in the Fe subnetwork. The mean field theory was used to analyze the temperature variation of the magnetization yielding smaller TM spin values and exchange coupling constants as compared with those of the Gd and Tb analogs. The uniaxial anisotropy constant {ital K}{sub {ital u}} for Dy-Co based alloys was found to vary with the square of the Dy subnetwork magnetization as predicted by the random single-ion theory. The anisotropy of Dy-Fe and Ho based alloys require additionally dipolar terms to account for the measured temperature dependence of {ital K}{sub {ital u}}. The coercive field {ital H}{sub {ital c}} follows a relation {ital H}{sub {ital c}} {similar to} {ital K}{sup 1.5}{sub {ital u}}/{ital M}{sub {ital s}}. The magneto-optical effects are primarily caused by the transition metals and therefore their compositional, temperature, and spectral dependence correspond to that of their Gd and Tb analogs. Optical recording experiments on Dy-FeCo disks yield good write and erase sensitivities and carrier-to-noise ratios up to 60 dB which are comparable to those of GdTb-Fe and Tb-FeCo disks.},
doi = {10.1063/1.348561},
journal = {Journal of Applied Physics; (USA)},
issn = {0021-8979},
number = ,
volume = 69:5,
place = {United States},
year = {1991},
month = {3}
}