Magnetothermal properties of Ho1_xDyxAl2 (x=0, 0.05, 0.10, 0.15, 0.25 and 0.50) compounds

Magnetic and magnetocaloric properties of Ho1_xDyxAl2 compounds with x = 0, 0.05, 0.10, 0.15, 0.25 and 0.50, modelled using a Hamiltonian that includes the exchange interactions between Ho-Dy, Ho-Ho and Dy-Dy ions in addition to the crystalline electric field and the Zeeman effects, have been compared with those determined experimentally. In order to reproduce experimentally observed global ferromagnetic ordering temperatures and spin reorientation transition temperatures as xDy varies, the exchange interactions between Ho-Dy and Ho-Ho were set as free parameters and adjusted to match the experimental results. We demonstrate that heat capacity of polycrystalline materials in non-zero magnetic fields can be satisfactory reproduced by using the average of multiple magnetic field directions with respect to the crystallographic coordinate system, while reasonably good agreement between experimentally determined and theoretically predicted magnetocaloric effects can be achieved considering an average of only three field directions.

Automated summary

The study compared the magnetic and magnetocaloric properties of Ho1_xDyxAl2 compounds with experimental results by adjusting the exchange interactions between ions and demonstrated that using the average of multiple magnetic field directions can reproduce the heat capacity of polycrystalline materials satisfactorily. Additionally, reasonably good agreement between experimentally determined and theoretically predicted magnetocaloric effects can be achieved by considering an average of only three field directions.