Magnetic properties of amorphous neodymium–transition‐metal films
作者:
R. C. Taylor,
T. R. McGuire,
J. M. D. Coey,
A. Gangulee,
期刊:
Journal of Applied Physics
(AIP Available online 1978)
卷期:
Volume 49,
issue 5
页码: 2885-2893
ISSN:0021-8979
年代: 1978
DOI:10.1063/1.325172
出版商: AIP
数据来源: AIP
摘要:
Amorphous thin films of NdxCo1−xand NdxFe1−xalloys were prepared over the compositional range 0.08⩽x⩽0.71 by e‐beam evaporation. Magnetization and anisotropy of the samples were studied over a wide temperature range with the aid of a force balance magnetometer, Hall effect measurements, and Mo¨ssbauer spectroscopy. It was found that the magnetization of the alloys could not be accounted for by a completely collinear alignment (ferromagnetic) of the Nd and transition‐metal subnetworks. Mean field analysis of the magnetization data showed a large reduction of the Nd–transition‐metal exchange coupling as compared to their Gd analogs. A model was developed which requires that Nd be dispersed in a cone whose axis is parallel to that of the transition‐metal subnetwork by strong coupling to randomly oriented local crystal field axes. This dispersion reduces the Nd net moment to 77&percent; of its free‐ion moment in NdxCo1−xalloys and to 25&percent; of its free‐ion moment in NdxFe1−xalloys. There is evidence that some dispersion also occurs in the Fe subnetwork. Anisotropy in NdxCo1−xalloys was found to be proportional to the square of the Nd subnetwork magnetization,Ku=CM2Nd.Cwas exponentially dependent on concentration according to the relationC=6 exp(−10x).
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