Proximity-Enhanced Magnetocaloric Effect in Ferromagnetic Trilayers

Abstract

The demagnetization and associated magnetocaloric effect in strong-weak-strong ferromagnetic trilayers, upon a reorientation of the strong ferromagnets from parallel to antiparallel magnetization, is simulated using atomistic spin dynamics. The simulations yield non-trivial spin distributions in the antiparallel state, which in turn allows entropy to be calculated directly. Empirical functional forms are obtained for the magnetization distribution in the spacer, differing significantly from some of the commonly used models. Finally, we find that the magnetocaloric effect in the system can be significantly improved by allowing the local exchange to vary through the spacer, which in practice can be implemented by spatially tailoring the spacer's magnetic dilution.

Magnetocaloric effect in multilayers studied by membrane-based calorimetry

“…A computationally efficient phenomenological model was developed for large phase-space mapping of our system, which is difficult to do using other approaches, such as the well-established but more resource intensive atomistic spin dynamics. (The latter is discussed in detail elsewhere [45], showing good qualitative agreement with the conclusion herein in regions of overlapping parameter space, e.g. when only short-range exchange is present).…”

“…Atomistic spin simulations of our system [45], which would incorporate long-range spin-spin interactions (the full width of the spacer of 6 nm, up to the 591st nearest neighbors), would be extremely time-and resource-consuming. We, therefore, develop here a phenomenological computational model [46], simulating the F/f/F system as a stack of magnetization vectors representing atomic monolayers throughout the trilayer.…”