We report structural, magnetic, transport, and thermal properties of single-crystal Ca2Ru1−xIrxO4(0≤x≤0.65). Ca2RuO4 is a structurally driven Mott insulator with a metal-insulator transition at TMI=357K, which is well separated from antiferromagnetic order at TN=110K. Substitution of a 5d 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 Ru/IrO6 octahedra and induces weak ferromagnetic behavior along the c axis. In particular, Ir doping suppresses TN but concurrently causes an additional magnetic ordering TN2 at a higher temperature up to 210 K for x=0.65. The effect of Ir doping sharply contrasts with that of 3d-element doping such as Cr, Mn, and Fe, which suppresses TN and induces unusual negative volume thermal expansion. The stark difference between 3d- and 5d-element doping underlines a strong magnetoelastic coupling inherent in the Ir-rich oxides.
Digital Object Identifier (DOI)
This work was supported by the National Science Foundation via Grant No. DMR-1265162 and China Scholarship Council (J.C.W.).
Yuan, Shujuan; Terzic, Jsaminka; Wang, J. C.; Li, L.; Aswartham, Saicharan; Song, W. H.; Ye, F.; and Cao, Gang, "Evolution of magnetism in single-crystal Ca2Ru1−xIrxO4(0≤x≤0.65)" (2015). Physics and Astronomy Faculty Publications. 300.
Supplementary Material: Word Document
Supplemental_Material-Yuan.pdf (236 kB)
Supplementary Material: PDF
Fig. 1.png (98 kB)
Fig. 2.png (220 kB)
Fig. 3.png (97 kB)
Fig. 4.png (95 kB)
Fig. 5.png (123 kB)
Fig. 6.png (62 kB)