Polaronic transport induced by competing interfacial magnetic order in a La$_{0.7}$Ca$_{0.3}$MnO$_{3}$/BiFeO$_{3}$ heterostructure

TL;DR

This study reveals that polaronic transport driven by interfacial magnetic order in LaCaMnO3/BiFeO3 heterostructures can be tuned via ferroelectric switching, impacting magnetotransport properties and advancing multiferroic device understanding.

Contribution

It demonstrates that interfacial antiferromagnetic order induces polaronic behavior affecting magnetotransport, a novel insight into magnetoelectric coupling mechanisms in heterostructures.

Findings

Polaronic behavior is linked to interfacial antiferromagnetic order.

Magnetic fields reduce polaronic features by increasing spin alignment.

Ferroelectric switching modulates polaronic transport in the heterostructure.

Abstract

Using ultrafast optical spectroscopy, we show that polaronic behavior associated with interfacial antiferromagnetic order is likely the origin of tunable magnetotransport upon switching the ferroelectric polarity in a La$_{0.7}$Ca$_{0.3}$MnO$_{3}$/BiFeO$_{3}$ (LCMO/BFO) heterostructure. This is revealed through the difference in dynamic spectral weight transfer between LCMO and LCMO/BFO at low temperatures, which indicates that transport in LCMO/BFO is polaronic in nature. This polaronic feature in LCMO/BFO decreases in relatively high magnetic fields due to the increased spin alignment, while no discernible change is found in the LCMO film at low temperatures. These results thus shed new light on the intrinsic mechanisms governing magnetoelectric coupling in this heterostructure, potentially offering a new route to enhancing multiferroic functionality.