Pressure effects on crystal structures and magnetic properties of RCo5 (R = Y or Gd) compounds

The pressure dependences of crystal structures and magnetic properties of YCo5 and GdCo5 compounds are analysed based on band structure calculations. Isomorphic transitions were evidenced for relative volumes v/v0 = 0.91 and 0.86, for YCo5 and GdCo5, respectively. At the transition, there is a higher decrease of cobalt moments at 3g sites as compared to those located in 2c ones. The induced polarizations on Y4d and Gd5d bands, by short range interactions, are linearly dependent on the magnetizations of cobalt atoms situated in their neighborhood. The isomorphic transitions are analysed in correlations with band structures.