Uncompensated magnetization and exchange-bias field in La$_{0.7}$Sr$_{0.3}$MnO$_3$/YMnO$_3$ bilayers: The influence of the ferromagnetic layer

TL;DR

This study investigates the magnetic properties of La$_{0.7}$Sr$_{0.3}$MnO$_3$/YMnO$_3$ bilayers, revealing significant uncompensated magnetization and complex exchange bias behavior influenced by the ferromagnetic layer's properties.

Contribution

It provides new insights into how the ferromagnetic layer affects magnetization shifts and exchange bias in multiferroic/ferromagnetic bilayers, highlighting the contribution of ferromagnetic properties.

Findings

Large vertical magnetization shifts up to 100% of the YMnO$_3$ saturation value.

The ferromagnetic layer significantly influences the magnetization shift.

No straightforward correlation between magnetization shift and exchange bias field.

Abstract

We studied the magnetic behavior of bilayers of multiferroic and nominally antiferromagnetic o-YMnO$_3$ (375~nm thick) and ferromagnetic La$_{0.7}$Sr$_{0.3}$MnO$_3$ and La$_{0.67}$Ca$_{0.33}$MnO$_3$ ($8 \ldots 225~$nm), in particular the vertical magnetization shift $M_E$ and exchange bias field $H_E$ for different thickness and magnetic dilution of the ferromagnetic layer at different temperatures and cooling fields. We have found very large $M_E$ shifts equivalent to up to 100\% of the saturation value of the o-YMO layer alone. The overall behavior indicates that the properties of the ferromagnetic layer contribute substantially to the $M_E$ shift and that this does not correlate straightforwardly with the measured exchange bias field $H_E$.