Magnetism in TmCo₂

Recently a new wave of interest in physics of RCo₂ compounds has been boosted by reports on unusual magnetic short range order configurations in the heavy rare-earth RCo₂ ferrimagnets in paramagnetic state. The newly observed phenomenon called parimagnetism consists in a short-range antiferromagnetic coupling between small ferromagnetic Co clusters and the nearest rare-earth moments. This paper is devoted to results of our experimental investigation of carefully prepared and characterized samples of TmCo₂, a compound on which controversial results can be found in literature. Detailed magnetization, AC susceptibility, specific heat and electrical resistivity measurements revealed two magnetic phase transitions at 4.6 and 3.6 K, respectively. The anomalies connected with the transitions are strongly dependent on magnetic field and hydrostatic pressure. The AC susceptibility anomaly connected with the onset of parimagnetism has been found at $T_{f}$=35 K. Contrary to other heavy rare-earth RCo₂ counterparts $T_{f}$ of TmCo₂ is entirely pressure independent.