Correlations between magnetism, microstructure, crystallography, and phase stability in GdNi1−xCox alloys

Abstract Relationships between the electronic structure, magnetostriction, and phase stability of the GdNi 1− x Co x system have been investigated. Increasing the concentration of Co in GdNi 1− x Co x (0 ⩽  x T C . The magnetic field and temperature dependent X-ray powder diffraction study of GdNi 0.85 Co 0.15 shows that the strong linear thermal expansion effects near T C are, however, absent. Density functional theory calculations show that hypothetical “GdCo” has positive formation energy, and density of states at the Fermi level indicates intrinsic instability of “GdCo” as opposed to GdNi. The enhanced exchange interaction energy of “GdCo” compared to GdNi supports the experimentally observed increasing Curie temperature of GdNi 1− x Co x with increasing x (Co).