Orbital magnetism in double perovskite compounds under extreme conditions by synchrotron radiation techniques

Abstract

We propose to study the electronic and magnetic properties of "Iridates" (Iridium containing oxides) where sizable spin-orbit interactions in third-row transition metal Ir ions lead to novel properties not achievable in oxides with first- and second-row transition metal ions. Double perovskite Sr2FeIrO6 displays competition between ferromagnetic and antiferromagnetic interactions, and the magnetic ground state can be tuned by alteration of Ir valence and/or lattice distortion. The layered iridate, Na2IrO3, displays competition between isotropic and anisotropic exchange interactions with a ground state in proximity to a a quantum spin liquid. We will use pressure as an external parameter to tune the electronic and magnetic ground states and probe emergence of novel properties at low temperatures with x-ray absorption near edge spectroscopy (XANES), x-ray magnetic circular dichroism (XMCD) and x- ray resonant magnetic scattering (XRMS) techniques at synchrotron light sources. These project includes commissioning of a panoramic diamond anvil cell (DAC) for XRMS measurements. The post-doctoral scientist Dr. Escanhoela will collaborate with the Magnetic Materials Group of the Advanced Photon Source (APS - USA) under the scientific supervision of Dr. Daniel Haskel, where he will perform experiments with techniques and instrumentation that are not yet available in Brazil. (AU)