GdCo₅ may be considered as two sublattices—one of Gd and one of Co—whose magnetizations are in antiparallel alignment, forming a ferrimagnet. Substituting cobalt with nickel weakens the magnetism of the Co sublattice, and can lead to the doped compound having zero net magnetic moment - a phenomenon known as compensation. In this work, we synthesized and characterized a number of samples with differing nickel content, and paired the experiments with calculations in order to explain the observed behaviour. Compensation is observed for nickel contents 1 < x < 3 at a temperature which increases with nickel content. A peak in the coercivity is seen at x~1 at 10 K which coincides with a minimum in the saturation magnetization. The density-functional theory calculations reproduce the temperature-dependent behaviour of the magnetization with nickel content, and also find a peak in the magnetocrystalline anisotropy close to the experimentally-observed coercivity maximum.

Journal reference: Phys. Rev. Materials 3, 034409 (2019)