Calorimetric study of the green phases R 2BaCuO 5 (R = Gd, Dy, Ho, Er, Lu, Y)

Adiabatic heat-capacity measurements between 5 and 60 K have been performed on a series of green phases R ₂BaCuO ₅. Independent peaks are generally observed for the three-dimensional magnetic ordering of the Cu and the magnetic rare earth ions. Contrarily, the compounds with nonmagnetic rare earth ions show rounded anomalies characteristic of low-dimensional magnetic interactions.