Tunable thermal hysteresis in magnetic multilayers: magnetic superheating and supercooling

The phenomena of superheating and supercooling can lead to a thermal hysteresis curve where two states are stable over a range of temperatures. Here we present a simple magnetic multilayer system (Fe/Gd) that can be designed to show a thermal hysteresis curve. Calculations show that, with proper choice of parameters, the width, in temperature, of the hysteresis curve can be controlled by an external magnetic field and varies from 20 to 100 K over a field range of 300-600 Oe. Polarized neutron reflectivity measurements confirm that such behavior is realized experimentally in multilayers of Fe/Gd.