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Dilute stuffing in the pyrochlore iridate Eu2Ir2O7

Telang, Prachi and Mishra, Kshiti and Sood, A K and Singh, Surjeet (2018) Dilute stuffing in the pyrochlore iridate Eu2Ir2O7. In: PHYSICAL REVIEW B, 97 (23).

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Official URL: https://dx.doi.org/10.1103/PhysRevB.97.235118


The pyrochlore Eu2Ir2O7 has recently attracted significant attention as a candidate Weyl semimetal. The previous reports on this compound unanimously show a thermally induced metal-to-insulator (MI) transition, concomitant with antiferromagnetic long-range ordering of the Jr moments below T-N similar to 120 K. However, there are contradictory reports concerning the slope d rho/dT of the resistivity plots (rho) in the ``metallic'' state above the MI transition, and the value of rho in the insulating state, both of which show significant sample dependence. Here, we explore this issue by investigating six different Eu2Ir2O7 samples with slightly varying Eu:Ir ratio. High-resolution synchrotron powder diffraction is done to probe minor variations in the cell parameters of the various Eu2Ir2O7 samples investigated here. Specific heat (C-p) and magnetic susceptibility of all the samples showed long-range antiferromagnetic ordering upon cooling below T-N similar to 120 K. The transitions are, however, found to be smeared out for the off-stoichiometric samples. We show that the sign of d rho/dT above the MI transition is highly sensitive to the unit-cell length, which, in turn, depends on the level of Eu stuffing at the Jr site. Samples with composition close to the ideal stoichiometry (Eu:Ir = 1) showed a change of sign of d rho/dT from negative to positive upon cooling below a certain temperature T* > T-MI. With increasing Eu stuffing, T* decreased until a negative d rho/dT persisted without any sign change down to T-MI.

Item Type: Journal Article
Additional Information: Copyright of this article belong to AMER PHYSICAL SOC, ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 03 Jul 2018 14:49
Last Modified: 25 Aug 2022 11:55
URI: https://eprints.iisc.ac.in/id/eprint/60125

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