Abstract
We report structural, magnetic, transport, and thermal properties of single-crystal . is a structurally driven Mott insulator with a metal-insulator transition at , which is well separated from antiferromagnetic order at . Substitution of a element, Ir, for Ru enhances spin-orbit coupling and locking between the structural distortions and magnetic moment canting. Ir doping intensifies the distortion or rotation of octahedra and induces weak ferromagnetic behavior along the axis. In particular, Ir doping suppresses but concurrently causes an additional magnetic ordering at a higher temperature up to 210 K for . The effect of Ir doping sharply contrasts with that of -element doping such as Cr, Mn, and Fe, which suppresses and induces unusual negative volume thermal expansion. The stark difference between - and -element doping underlines a strong magnetoelastic coupling inherent in the Ir-rich oxides.
- Received 7 April 2015
DOI:https://doi.org/10.1103/PhysRevB.92.024425
©2015 American Physical Society