Exchange bias training effect in IrMn-layer/ferromagnetic-ribbon heterostructures probed with magnetoimpedance

TL;DR

This study investigates the exchange bias training effect in IrMn-layer/ferromagnetic-ribbon heterostructures using magnetoimpedance measurements, revealing significant shifts and asymmetries linked to the training effect and confirming Hoffmann's model.

Contribution

It demonstrates the application of magnetoimpedance measurements to analyze the exchange bias training effect in IrMn/ferromagnetic heterostructures, confirming Hoffmann's model as an accurate description.

Findings

52% increase in MI at zero field indicating exchange bias

Decrease in EB field and asymmetry during field sweeps

Strong single-cycle training effect consistent with Hoffmann's model

Abstract

The exchange-bias training effect in IrMn-layer/ferromagnetic-ribbon heterostructure is studied by performing magnetoimpedance (MI) measurements. Asymmetric, hysteretic and single peak behavior of the MI response and a shift in the MI peak to zero fields accompanied by 52% increase in MI has been detected as the signature of the exchange bias (EB) and training effect (TE), respectively. Also, during the consecutive filed sweep of MI response, both EB field and the degree of asymmetry of MI decrease that is another reason for existence of TE in our sample. The analysis of the magneto-optical Kerr effect (MOKE) and MI behavior establish that Hoffmann s model (Phys. Rev. Lett. 93, 097203 (2004)) is a good description of our experimental data, due to the existence of a strong single cycle TE in our IrMn-layer/ferromagnetic-ribbon system.