Magnetic properties of the Y1-xLaxCo4B (x=0 to 1) pseudoternary compounds: High and low field studies
The YCo4B compound is known to crystalline in the CeCo4B structure with an average Co magnetic moment of 0.7μB which is much smaller than the Co moment of 1.6μB in YCo5. Previously, we have shown that the basal-plane anisotropy of Co in YCo4B changes into easy-axis with increasing temperature (around 150K) or by substituting of La by Y. The present study has been carried out on free-powder and magnetically-aligned Y1-xLaxCo4B samples with x=0.0, 0.2, 0.5, 0.8 and 1.0. Magnetisation measurements were performed at 4.2 K in low (static) fields (up to 4 T) and in high pulsed fields (up to 35 T). The main results are: i) up to 35 T, no transition is observed, the high-field susceptibility shows an induced Co moment of 0.004μB/T; ii) at 4.2 K the compounds with x=0.8 and 1.0 show easy-axis anisotropy, whereas the others have easy-plane anisotropy; iii) the saturation magnetisation is anisotropic with Δσ/σs values increasing from 0.008 for YCo4B to 0.03 for LaCo4B. This magnetisation anisotropy is compared to the ratio of the magnetocrystalline anisotropy energy and the exchange energy. © 1992.