INFLUENCE OF AN APPLIED MAGNETIC FIELD ON THE STRUCTURAL TRANSITIONS IN RCo_2 (R = Dy, Ho, Er) COMPOUNDS

摘要

Application of an external magnetic field decreases the degree of lattice distortions in RCo_2 compounds (R = Dy, Ho, Er) promoting the formation of the cubic phase. The unit-cell volume changes are sharper in HoCo_2 and ErCo_2 than in DyCo_2 where the transition becomes of a second-order in magnetic fields ≥4 T in agreement with reported DSC and heat capacity results. The apparent change of the transition order in applied magnetic field does not have much effect on the magnetocaloric properties; however, the size of the volume change in zero magnetic field is an important characteristic of the material with respect to its magnetocaloric properties.