Magnetism in RCo2 (R = Dy, Ho, Er, Tm) Under Hydrostatic Pressure

The short-range parimagnetic configurations, observed in the heavy rare-earth RCo2 compounds in paramag-netic range far above the Curie temperature TC, consist in formation of ferromagnetic cobalt clusters antiferro-magnetically coupled to the neighboring R magnetic moments. The characteristic temperature of the onset of parimagnetism Tf is very sensitive to changes of external conditions like pressure or composition. The pressure coefficients ∂Tf/∂p and ∂TC/∂p are comparable, indicating a close connection of underlying mechanisms. Our recent measurements indicate systematic evolution of the pressure coefficients with spanning the rare-earth series from Dy through Tm in RCo2 with a specific case TmCo2