Comparison of isothermal and adiabatic magnetocaloric effects in Gd films and microwires

A comparative analysis of the temperature and field dependences of the magnetization of Gd films and microwires was carried out, as well as an analysis of isothermal and adiabatic changes in the magnetic part of the entropy and heat capacity at temperatures close to the Curie temperature. The magnetocaloric effect in microwires exhibits two peaks at $\sim$290 and $\sim$320 K in the temperature dependence of the magnetic part of the entropy, in contrast to one peak in films. In films and microwires, the entropy maximum at $\sim$290 K depends on the magnetic field, shifting equally in films and microwires with increasing field. In microwires, the second maximum at $\sim$320 K does not change its position as the field increases to 9 T, but its amplitude increases linearly with increasing field. This maximum is due to a spin-reorientation transition in the phase with an increased Curie temperature.