GdCo5 may be considered as two sublattices - one of Gd and one of Co - whose magnetizations are in antiparallel alignment, forming a ferrimagnet. Substitution of nickel in the cobalt sublattice of GdCo5 has been investigated to gain insight into how the magnetic properties of this prototype rare-earth/transition-metal magnet are affected by changes in the transition metal sublattice. Polycrystalline samples of GdCo5−xNix for 0 ≤x≤ 5 were synthesized by arc melting. Structural characterization was carried out by powder x-ray diffraction and optical and scanning electron microscope imaging of metallographic slides, the latter revealing a low concentration of Gd2(Co, Ni)7 lamellae for x≤2.5. Compensation - i.e. the cancellation of the opposing Gd and transition metal moments is observed for 1≤x≤3 at a temperature which increases with Ni content; for larger x, no compensation is observed below 360 K. A peak in the coercivity is seen at x≈1 at 10K coinciding with a minimum in the saturation magnetization. Density-functional theory calculations within the disordered local moment picture reproduce the dependence of the magnetization on Ni content and temperature. The calculations also show a peak in the magnetocrystalline anisotropy at similar Ni concentrations to the experimentally observed coercivity maximum.
@article{arxiv.1903.11442,
title = {Structural and magnetic properties of GdCo$_{5-x}$Ni$_x$},
author = {Amy L. Tedstone and Christopher E. Patrick and Santosh Kumar and Rachel S. Edwards and Martin R. Lees and Geetha Balakrishnan and Julie B. Staunton},
journal= {arXiv preprint arXiv:1903.11442},
year = {2019}
}