Influence of electrostatic gating on the proximity induced magnetisation in SrIrO3

We recently reported on strong anomalous Hall effect (AHE) in heterostructures of non-magnetic SrIrO3 (SIO) and ferromagnetic LaCoO3 (LCO) which demonstrated proximity-induced ferromagnetism in SIO.[1] Latest experiments on SIO/LCO heterostructures show large tunability of the AHE by electrostatic gating where the Hall conductivity or Hall angle was changed by up to 600%.[2] In contrast, the rather small Ir magnetic moment of 0.018 mB as deduced from x-ray magnetic circular dichroism (XMCD) at the Ir L edge,[3] raises question on the origin of the large AHE and its tuneability. In the following, we therefore propose XMCD measurements at the Ir L edge at the beam line ID12 on a selection of high quality SIO/LCO heterostructures to study the Ir magnetic moment as a function of the gate voltage Vg. Specifically, we aim to investigate the orbital and spin moment of Ir as well as possible changes in the density of unoccupied Ir 5d states as a function of Vg.