To clarify the electronic, lattice, and magnetic contribution to the inverse magnetocaloric effect (IMCE) in the metamagnetic shape-memory alloy ${\mathrm{Ni}}_{45}{\mathrm{Co}}_5{\mathrm{Mn}}_{50-x}{\mathrm{In}}_x$, magnetization, magnetocaloric effect, and specific-heat measurements were carried out in a wide range of fields and temperatures. The IMCEs of ${\mathrm{Ni}}_{45}{\mathrm{Co}}_5{\mathrm{Mn}}_{36.7}{\mathrm{In}}_{13.3}$ were directly measured as adiabatic temperature changes in pulsed fields of up to 15 T. A maximum temperature decrease of $-12.8$ K was observed. The low-temperature specific heats in both the austenitic and the martensitic phases of ${\mathrm{Ni}}_{45}{\mathrm{Co}}_5{\mathrm{Mn}}_{36.5}{\mathrm{In}}_{13.5}$ were measured by using steady fields. Through analyses of the data, the entropy changes in charge (1.2 J/kg K), spin $(-29$ J/kg K), and lattice (51 J/kg K) sectors were individually evaluated. The result demonstrates the dominant role of the lattice sector in inverse MCEs in this material.

• Received 2 December 2013
• Revised 17 September 2014

DOI:https://doi.org/10.1103/PhysRevB.90.214409