Magnetic properties of R(Co_(0.88)Fe_(0.12))_2 quasi-binary compounds

摘要

In this paper the results of magnetic properties study for a series samples of R(Co_(0.88)Fe_(0.12))_2 type intermetallic compounds with a heavy rare-earth elements (R = Gd, Tb, Dy, Ho, Er) are presented. Such materials having a plateau-like temperature dependences of magnetic entropy change in the temperature range lower Curie point are considered as a promising functional materials for magnetic refrigerators. Their phase composition was controlled by X-ray diffraction analysis with a help of Bruker D8 Advance diffractometer. Magnetic field magnetization dependences - M(H) were measured using a SQUID magnetometer (MPMS-XL-7, Quantum Design) within the temperature range of 5 - 600 K in magnetic fields up to 5600 kA/m. The crystal lattice parameter - a, Curie temperature - T_C, coercivity - H_c and residual magnetization - M_r values are analyzed as a functions of R-element atomic number. For compounds with Tb, Dy, Ho and Er the second picks on the high field susceptibility temperature dependences - χ_(hf)(T) were found in the temperature range lower their T_C.