Magnetic and Thermomagnetic Properties of Materials Based on R (Co 1 – x Fe x ) 2 Laves Phases with Heavy Rare-Earth Metals

The crystal structure, the temperature and field dependences of the magnetization M and of the magnetic contribution into the entropy Δ S m , the temperature dependences of the high-field susceptibility χ and the heat capacity C p of specimens of polycrystal R (Co 1 – x Fe x ) 2 compounds, where R is Gd, Dy, Ho or Er, are studied. The width of the Δ S m peak at half-height of its maximum (Δ T FWHM ) is estimated. The dependences of Δ T FWHM and of the temperature behavior of Δ S m of the specimens on the magnetic field, on the iron content ( x ) and on the atomic number of the element R are determined. The causes of the broadening of the Δ S m ( T ) peak upon substitution of cobalt with iron in the R (Co 1 – x Fe x ) 2 compounds are considered.