Effects of high pressure on the magnetism of ErCo₂

This paper presents the results of a high pressure study on the ferrimagnetic compound ErCo₂, which exhibits at ambient pressure magnetic ordering below T_C = 33 K, where the localized Er magnetic moments order ferromagnetically, and the itinerant moments in the Co sublattice, align antiparallel to the Er moments. In the paramagnetic range, clustering of the Co moments is observed below T_f ∼ 100 K for which the term “parimagnetism” has been proposed. In contrast to the pronounced peak in the AC susceptibility data at T_C only a tiny “bump” shows up at T_f. The decrease of both T_C and T_f with applied hydrostatic pressure has been observed, the first one being in agreement with previously published data. At higher pressures, an asymmetry in the T_C-related AC susceptibility peak has been observed owing to a decoupling of the magnetic ordering phenomena in the Er and Co sublattices. Compared to earlier published results, our magnetization measurements at higher pressures above P_C reveal a small but clearly observable evolution of both the critical temperature and saturated magnetization.