Why the Co-based 115 compounds are different: The case study of GdMIn5 (M=Co,Rh,Ir)

JORGE I. FACIO; DIANA BETANCOURTH; PABLO PEDRAZZINI; P.G. PAGLIUSO; V.F. CORREA; V. VILDOSOLA; D.J. GARCÍA; PABLO S. CORNAGLIA

Bariloche

Conferencia; Advanced Topics in Magnetism and Superconductivity; 2014

We analyse a regularity experimentally observed in the RMIn 5 (R=rare earth, M=Co, Rh, Ir) family of compounds where the lowest Néel temperatures are obtained in the Co?basedmaterials. We focus our analysis on the GdMIn 5 compounds and perform density functional theory based total energy calculations to obtain their equilibrium structures, phonon spectra and the parameters for the exchange coupling interactions between the magnetic moments located at the Gd ions. We obtain excellent agreement of the calculated Néel and Curie-Weiss temperatures, the specific heat including the lattice, magnetic and electronic contributions, and the magnetic susceptibility with the existent experimental data. The interplane exchange coupling in the Co-based material is much smaller than in the Rh and Ir analogues which explains its observed lower Néel temperature.