1. Magnetic order and spin-orbit coupled Mott state in double perovskite (La$_{1-x}$Sr$_x$)$_2$CuIrO$_6$
- Author
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Zhu, W. K., Tung, J. -C., Tong, W., Ling, L., Starr, M., Wang, J. M., Yang, W. C., Losovyj, Y., Zhou, H. D., Wang, Y. Q., Lee, P. -H., Wang, Y. -K., Lu, Chi-Ken, and Zhang, S. X.
- Subjects
Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Materials Science ,Condensed Matter::Materials Science ,Strongly Correlated Electrons (cond-mat.str-el) ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Condensed Matter::Strongly Correlated Electrons ,Computational Physics (physics.comp-ph) ,Physics - Computational Physics - Abstract
Double-perovskite oxides that contain both 3d and 5d transition metal elements have attracted growing interest as they provide a model system to study the interplay of strong electron interaction and large spin-orbit coupling (SOC). Here, we report on experimental and theoretical studies of the magnetic and electronic properties of double-perovskites (La$_{1-x}$Sr$_x$)$_2$CuIrO$_6$ ($x$ = 0.0, 0.1, 0.2, and 0.3). The undoped La$_2$CuIrO$_6$ undergoes a magnetic phase transition from paramagnetism to antiferromagnetism at T$_N$ $\sim$ 74 K and exhibits a weak ferromagnetic behavior below $T_C$ $\sim$ 52 K. Two-dimensional magnetism that was observed in many other Cu-based double-perovskites is absent in our samples, which may be due to the existence of weak Cu-Ir exchange interaction. First-principle density-functional theory (DFT) calculations show canted antiferromagnetic (AFM) order in both Cu$^{2+}$ and Ir$^{4+}$ sublattices, which gives rise to weak ferromagnetism. Electronic structure calculations suggest that La$_2$CuIrO$_6$ is an SOC-driven Mott insulator with an energy gap of $\sim$ 0.3 eV. Sr-doping decreases the magnetic ordering temperatures ($T_N$ and $T_C$) and suppresses the electrical resistivity. The high temperatures resistivity can be fitted using a variable-range-hopping model, consistent with the existence of disorders in these double-pervoskite compounds., Comment: Submitted; updated and added references in v2
- Published
- 2016
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