Polarity and spin-orbit coupling induced large interfacial exchange coupling an asymmetric charge transfer in iridate-manganite heterostructure

TL;DR

This study demonstrates how polarity and spin-orbit coupling at the interface of iridate-manganite heterostructures induce large exchange bias and asymmetric charge transfer, revealing new ways to manipulate interface physics in transition-metal oxides.

Contribution

It uncovers the role of polarity and spin-orbit interaction in enhancing interfacial magnetic coupling and charge transfer in oxide heterostructures, supported by experiments and first-principles calculations.

Findings

Large exchange bias observed in LaMnO3/SrIrO3 bilayers.

Enhanced coercivity of LaMnO3 due to interfacial effects.

Asymmetric charge transfer driven by polarity and spin-orbit coupling.

Abstract

Charge transfer is of particular importance in manipulating the interface physics in transition-metal oxide heterostructures. In this work, we have fabricated epitaxial bilayers composed of polar 3d LaMnO3 and nonpolar 5d SrIrO3. Systematic magnetic measurements reveal an unexpectedly large exchange bias effect in the bilayer, together with a dramatic enhancement of the coercivity of LaMnO3. Based on first-principles calculations and x-ray absorption spectroscopy measurements, such a strong interfacial magnetic coupling is found closely associated with the polar nature of LaMnO3 and the strong spin-orbit interaction in SrIrO3, which collectively drives an asymmetric interfacial charge transfer and leads to the emergence of an interfacial spin glass state. Our study provides new insight into the charge transfer in transition-metal oxide heterostructures and offers a novel means to tune the interfacial exchange coupling for a variety of device applications.