Magnetic and Magnetocaloric Properties of the Tm 1 – x Y x (Co 0.84 Fe 0.16 ) 2 Compounds

The effect of substitution of yttrium for thulium in the Tm(Co 0.84 Fe 0.16 ) 2 compound on the crystal structure, temperature and field dependences of magnetization (σ), temperature dependences of the high-field susceptibility (χ hf ), isothermal magnetic entropy change (∆ S m ), and adiabatic temperature change (∆ T ad ) is studied. The magnetic and magnetocaloric properties were measured in magnetic fields up to 90 kOe in a temperature range of 5–380 K. The dependences σ( T ) measured in an external magnetic field of 100 Oe were found to exhibit the magnetization inversion. The field dependence of the magnetic moment of the Tm 0.4 Y 0.6 (Co 0.84 Fe 0.16 ) 2 compound, which is measured at 5 K, exhibits a point of inflection corresponding to a magnetic field of 49.5 kOe; the substantial increase in the magnetic field leads to an increase in the susceptibility of the sample to the magnetic field. Samples characterized by magnetic compensation temperature demonstrate the alternation of direct and inverse magnetocaloric effect (MCE). A number of the compounds under study exhibit the plateau-like temperature dependences of ∆ S m and ∆ T ad in a temperature range of inverse MCE. The results obtained are discussed.