Thermal hysteresis of magnetization in NiFe/IrMn exchange-biased ferromagnet

Abstract

Magnetization reversal in NiFe/IrMn exchange-biased thin films was investigated under thermal cycling in an external magnetic field, applied opposite to the direction of the exchange bias field. Thermal hysteresis of magnetization accompanied by changes in magnetization polarity was observed in the applied field close to the exchange bias value. This effect appears when thermally induced variations of the exchange bias exceed the corresponding variations in coercivity. The amplitude of magnetization reversal in NiFe/IrMn structures exceeds ~ 100 times the corresponding amplitude in spin-crossover molecular compounds. The observed bistability of the magnetic state, revealed by thermal hysteresis, gradually disappears with an increase in the number of cooling-heating thermal cycles, that indicates an irreversible quenching of the interfacial magnetization configuration. This effect paves the way for the creation of a new class of switching devices with thermally assisted bistability in the ferromagnetic state.

Connection Between Intrinsic Interfacial Frozen Spins and Exchange Bias Effect in Core@Shell Iron@Iron‐Oxide Nanoparticles

“…[ 12,13 ] The interface coupling between ferromagnetic core and ferrimagnetic shell is considered to be rigid, which can act as highly effective anisotropy. [ 14,15 ] As a result, larger magnetic fields are necessary to change the state of magnetic moments by increasing the Zeeman energy. Additionally, in single‐component nanoparticles, the exchange bias effect can be induced because of frozen spins on the interface of ferromagnetic/ferrimagnetic heterostructures under field‐cooling (FC) conditions.…”

Manipulating the magnetic and transport properties by CuIr thickness in CoFeB/CuIr/IrMn multilayers

“…Magnetic multilayered structures are attractive systems, as their magnetic and transport properties can be tailored by changing any of their layer properties [1][2][3][4][5][6][7][8][9][10][11]. This feature makes them of great technological importance, especially for spin-dependent applications such as spintronic sensors, memory devices and magnetoresistive biosensing platforms [10,[12][13][14][15].…”

“…For example, if a multilayered system contains exchange biased FM/AF layers, a non-magnetic (NM) spacer inserted between these two layers greatly alters the magnetic and transport properties of the stack [24]. In FM/AF multilayer structures where EB or magnetoresistive properties are desired to be investigated, nonmagnetic metals such as Au, Pt, Ta, and W are the most used materials as a spacer layer due to their contribution to multilayer with their high spin-orbit coupling [1,9,25]. The structures in which these spacers are frequently seen particularly in studies investigating spintronic applications [4][5][6][7]26].…”