ИСТИНА

The cubic Laves phase RCo2 compounds (R = rare-earth metal) are characterized by intrinsic instability of the Co-sublattice magnetic moments. In such compounds in the region of the Curie temperature, both a significant magnetostriction and a large magnetocaloric effect (MCE) are observed. Using various combinations of rare-earth metals and the partial substitution of a metal for Co, one may improve their properties and engineer new functional materials based on them. The present study is focused on analyzing of magnetic and structural features Tb-Dy-Ho-Co-T (T = Al, Fe) multicomponent alloys. The alloys of Tb0.3Dy0.35Ho0.35Co1.75T0.25 were synthesized in helium atmosphere in an electric arc furnace with followed by homogenizing annealing. The purity of Co and rare-earth metals was 99.99 and 99.9%, respectively. X-ray diffraction analysis shows that all compounds under study had single phase MgCu2-type structure. The temperature dependent of lattice parameters was investigated. The surface topology of the synthesized RCo2 Laves-phase samples was studied by atomic force microscopy using scanning probe microscope both in semicontact and contact modes at room temperature. The MCE was measured in fields of up to 1.8 T by direct method and magnetostriction was measured by the strain-gauge method in the temperature range 80 - 320 K in magnetic fields up to 1.2 T. The Curie temperature, values of MCE and magnetostriction were obtained. The relationship between magnetic properties and micro- and nanoscale structural features of samples was established.