High magnetocaloric efficiency of a NiFe/NiCu/CoFe/MnIr multilayer in a small magnetic field

The isothermal magnetic entropy changes are studied in Ni80Fe20/Ni67Cu33/Co90Cu10/Mn80Ir20 stacks at temperatures near the Curie point of the Ni67Cu33 spacer by applying magnetic fields in a few tens of Oersted. Such low fields were sufficient for toggling magnetic moments in the soft ferromagnetic (FM) layer (Ni80Fe20). It is found out that this switching provides the magnetic entropy change, which is up to 20 times larger than that achievable in a single Ni67Cu33 film subjected to such low fields. Our finding holds promise to be utilized in the magnetocaloric devices that would be based on FM/PM/FM heterostructures and would operate with moderate magnetic fields.