Publication Title

Journal of Physics Condensed Matter

Document Type

Article

Department or Program

Chemistry

Publication Date

11-5-2020

Keywords

iridate, metal insulator transition, Mott insulator, pyrochlore, spin-orbit coupling

Abstract

© 2020 IOP Publishing Ltd. In this study, we employ bulk electronic properties characterization and x-ray scattering/spectroscopy techniques to map the structural, magnetic and electronic properties of (Eu1-xCax)2Ir2O7 as a function of Ca-doping. As expected, the metal-insulator transition temperature, T MIT, decreases with Ca-doping until a metallic state is realized down to 2 K. In contrast, T AFM becomes decoupled from the MIT and (likely short-range) AFM order persists into the metallic regime. This decoupling is understood as a result of the onset of an electronically phase separated state, the occurrence of which seemingly depends on both synthesis method and rare earth site magnetism. PDF analysis suggests that electronic phase separation occurs without accompanying chemical phase segregation or changes in the short-range crystallographic symmetry while synchrotron x-ray diffraction confirms that there is no change in the long-range crystallographic symmetry. X-ray absorption measurements confirm the J eff = 1/2 character of (Eu1-xCax)2Ir2O7. Surprisingly these measurements also indicate a net electron doping, rather than the expected hole doping, indicating a compensatory mechanism. Lastly, XMCD measurements show a weak Ir magnetic polarization that is largely unaffected by Ca-doping. Keywords: term, term, term.

Comments

Original version is available from the publisher at: https://doi.org/10.1088/1361-648X/abbf2b

Copyright Note

This is the author's version of the work. This publication appears in Bates College's institutional repository by permission of the copyright owner for personal use, not for redistribution.

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