Exchange coupling induced antiferromagnetic-ferromagnetic transition in $Pr_{0.5}Ca_{0.5}MnO_3/La_{0.5}Ca_{0.5}MnO_3$ superlattices

TL;DR

This study investigates how varying the thickness of La_{0.5}Ca_{0.5}MnO_3 layers in superlattices with Pr_{0.5}Ca_{0.5}MnO_3 induces a transition from antiferromagnetic to ferromagnetic states due to interface strain effects.

Contribution

It demonstrates the control of magnetic phase transitions in superlattices through layer thickness and interface strain engineering.

Findings

AFM to FM transition observed with increasing LCMO thickness

Enhanced coercivity in superlattices

Presence of mixed magnetic phases at interfaces

Abstract

Superlattices built from two antiferromagnetic (AFM) charge/orbital order compounds, $Pr_{0.5}Ca_{0.5}MnO_3$ and $La_{0.5}Ca_{0.5}MnO_3$, have been studied as the thickness of $La_{0.5}Ca_{0.5}MnO_3$ ($LCMO$) varied. High structural quality thin films were obtained on $LaAlO_3$ substrates using the pulsed laser deposition technique. An antiferromagnetic-to-ferromagnetic transition, in addition to an enhancement of the coercivity, are observed as the $LCMO$ layer thickness increases. The small shift in the origin of the field-cooled hysteresis loop along the field axis indicates the presence of ferromagnetic and antiferromagnetic phases in the superlattices. We attribute these features to the AFM spin fluctuations at the $Pr_{0.5}Ca_{0.5}MnO_3/La_{0.5}Ca_{0.5}MnO_3$ interfaces resulting from the strain effects.