Hexagonal BaIrO3 is a magnetic insulator driven by the spin-orbit interaction (SOI), whereas BaRuO3 is an enhanced paramagnetic metal. Our investigation of structural, magnetic, transport, and thermal properties reveals that substitution of Ru4+ (4d4) ions for Ir4+ (5d5) ions in BaIrO3 reduces the magnitudes of the SOI and a monoclinic structural distortion and rebalances the competition between the SOI and the lattice degrees of freedom to render an evolution from a magnetic insulting state to a robust metallic state. The central findings of this paper are as follows: (1) light Ru doping (0 < x ≤ 0.15) prompts simultaneous, precipitous drops in both the magnetic ordering temperature TN and the electrical resistivity, and (2) heavier Ru doping (0.41 ≤ x ≤ 0.9) induces a robust metallic state without any long-range magnetic order. All results suggest a critical role of the lattice degrees of freedom in determining the ground state in the heavy transition-metal oxides.
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This work was supported by the National Science Foundation via Grant No. DMR-1265162 (G.C.) and Departmentof Energy (BES) through Grants No. DE-FG02-98ER45707(P.S.) and No. DE-FG02-97ER45653 (L.E.D.).
See Supplemental Material at https://journals.aps.org/prb/supplemental/10.1103/PhysRevB.93.165136 for substantial information on crystal refinements.
Yuan, Shujuan; Butrouna, Kamal H.; Terzic, Jsaminka; Zheng, Hao; Aswartham, Saicharan; DeLong, Lance E.; Ye, Feng; Schlottmann, P.; and Cao, Gang, "Ground-State Tuning of Metal-Insulator Transition by Compositional Variations in BaIr1−xRuxO3 (0 ≤ x ≤ 1)" (2016). Physics and Astronomy Faculty Publications. 445.