Controlling magnetism and electron transport through interface engineering in SrRuO₃/SrCuO₂ bilayer

Atomic-scale synthesis of oxide heterostructures provides a fertile ground for creating emergent interfacial phenomena. A specific reconstruction involving the absence of apical oxygen atom at the interface comprising the infinite-layer SrCuO₂(SCO) and perovskite SrRuO₃(SRO) is predicted to have enhanced Dzyaloshinskii-Moriya interaction (DMI)[1] that could result topological Hall effect (THE). In this regard, we have fabricated SRO/SCO bilayers on TiO₂ terminated SrTiO₃(001) using PLD to delve into the effect of DMI and interfacial orbital reconstruction on magnetic and magnetotransport properties of SRO. Magnetic measurements reveal a high spin state of Ru ion (S=3/2) in SRO(12u.c.)/SCO(8 u.c.) as compared to bare SRO layer. This is ascribed to the orbital reconstruction induced by the absence of apical oxygen atom at the interface. Hall transport carried out on relatively thick SRO(42 u.c.)/SCO(12 u.c.) bilayer did not yield any THE, rather exhibits anomalous Hall effect (AHE) with a sign change in the AHE coefficient (R_s) from negative to positive with increase in temperature. Further, to explore the possible occurrence of THE, we are investigating Hall transport on the SRO/SCO bilayers consisting of ultrathin SRO layer where the interfacial DMI will have a pronounced effect.

References:

1. Chen et al., Phys. Rev. B 105, 214428 (2022)