Tuning of magnetocaloric effect and optimization of scaling factor for Gd55Ni10Co35 amorphous microwires

We have investigated the Gd55Ni10Co35 amorphous microwires with a large supercooling temperature range of 132 K in terms of thermally induced microstructural evolution and their magnetocaloric effect (MCE). With the emerging and growth of the nanocrystals against the maintained amorphous matrix, there appears a threshold annealing temperature of 513 K where the Curie temperature (Tc) sees an abrupt increase from 192 K to 212 K as a result of competition between amorphous and crystalline phase. Another effect from these two phases is to conspire to a broadening of working temperature range. The scaling factor n as in ΔSM∝Hn is found to follow a Boltzmann type of dependency on the annealing temperature and can hence serve as an indicator for the desirable microstructure in favor of MCE. All these results demonstrate that the MCE performance of Gd-based amorphous microwires can be formulated via the fine control of microstructure.