A survey is given of the physical properties, composition and crystal structure of intermetallic compounds formed between rare-earth elements and 3d transition elements. Apart from binary compounds the results of pseudobinary series are also considered. The magnetic properties determined by the exchange interactions involving 4f as well as 3d electrons, are discussed together with experimental results available on magnetovolume effects and various resonance techniques such as NMR and the Mossbauer effect.

https://iopscience.iop.org/article/10.1088/0034-4885/40/10/002/pdf

Intermetallic compounds of rare-earth and 3d transition metals

Magnetic properties of GdxY1−xNi5 alloys

The magnetic properties of the Laves phase system Y(Fe1-cAlc)2 have been studied by means of bulk magnetisation measurements in fields up to 72 kOe for 0 or=n0=15 iron neighbours; this moment remains constant and equal to that of YFe2 at least up to 32.6 at.% Al. This model accounts for the variation with c of the spontaneous magnetisation related to the magnetic atoms, the high-field susceptibility which arises from the nonmagnetic Fe atoms, and for the hyperfine field distributions.

Magnetic and 57Fe Mossbauer study of Y(Fe1-cAlc)2 alloys: Local environment effects

Results of magnetic measurements, ferromagnetic resonance and electron paramagnetic resonance (EPR) studies of the Gd(CoxAl1−x)2 system are presented. These compounds are ferrimagnetic in the concentration range x > 0.55. The cobalt moment is markedly dependent on composition. The reciprocal susceptibility has a non-linear temperature dependence. The magnetic behaviour of these compounds is analysed using three models, namely the molecular field approximation, the model which assumes that cobalt has an exchange-enhanced paramagnetic susceptibility and the local environment model. All these describe the experimental data rather well. For x < 0.55 the compounds are ferromagnetic. In this case the reciprocal susceptibility follows a Curie-Weiss law.

For ferrimagnetic compounds the resonance data at 78 K are described using the Wangsness relation. The EPR measurements for x < 0.55 reveal that the slope of the linewidth b and the g values are not temperature dependent. For ferrimagnetic compounds both b and the g values are functions of temperature. These data are discussed in terms of a model based on the molecular field approximation. The composition dependences of gCo and gGd values are analysed.

Finally, the magnetic behaviour of cobalt atoms in pseudo-binary Laves phase compounds is discussed.

J.A. Cannon

Papers

Transition metal moment collapse in gadolinium-transition metal laves phase intermetallics

Temperature dependent splitting of the 59Co hyperfine field in GdCo2