Temperature induced itinerant electron metamagnetism in ErCO3 and HoCo3: influence of an external field and pressure

The rhombohedral compounds ErCo3 and HoCo3 order magnetically at 401 and 44 0 K, respectively. The magnetic properties at low temperatures are characte rized by a magnetic instability of their Co-sublattice (metamagnetism) and a spin reorientation in the R-sublattice in HoCo3. These phenomena have bee n studied by performing specific heat and resistivity measurements. Due to a special balance between the R-Co and Co-Co exchange interactions, a tempe rature-induced metamagnetic transition in the Co sublattice occurs in the i ntermetallics ErCO3 (at T-m varying between 65 and 100 K, depending on stoi chiometry) and HoCo3 (at T-m = 175 K). The application of an external magne tic field (magnetoresistance) and pressure show that the metamagnetic trans itions in the Co sublattice are strongly dependent on these parameters (par tial derivativeT(m)/partial derivativeP approximate to -7.5 K/kbar and part ial derivativeT(m)/partial derivativeH = - 1.1 K/Tesla). (C) 2001 Elsevier Science Ltd. All rights reserved.