High-pressure Synthesis of Cubic Perovskite KOsO₃ and Its Incommensurate Magnetic Structure

The syntheses of LiOsO₃ and NaOsO₃ revived the long-standing dialogs of ferroelectric metal and the metal-insulator transition [1-4]. A cubic perovskite phase of KOsO₃ in this family has been synthesized under a high-pressure and high-temperature condition for the first time. The neutron diffraction measurements were performed on the powder sample of KOsO₃ at 100, 200, 300, 400 and 500 K. The nuclear structure of KOsO₃ remains the simple cubic perovskite structure (Pm-3m) from 100 K to 500 K; surprisingly, its magnetic structure was determined to be incommensurate in the temperature range 100-500 K, and the propagation vector changes as temperature increases from 300 K to 500 K [figure 1 (b)]. In the talk, we will present the details of this rare incommensurate magnetic structure and its novel magnetism, as well as the electron transport and other physical properties of this new 5d perovskite.

[1] Y. Shi, Y. Guo, X. Wang, A. J. Princep, D. Khalyavin, P. Manuel, Y. Michiue, A. Sato, K. Tsuda, S. Yu, M. Arai, Y. Shirako, M. Akaogi, N. Wang, K. Yamaura, and A. T. Boothroyd, A ferroelectric-like structural transition in a metal, Nature Materials 12, 1024 (2013).

[2] Y. G. Shi, Y. F. Guo, S. Yu, M. Arai, A. A. Belik, A. Sato, K. Yamaura, E. Takayama-Muromachi, H. F. Tian, H. X. Yang, J. Q. Li, T. Varga, J. F. Mitchell, and S. Okamoto, Continuous metal-insulator transition of the antiferromagnetic perovskite NaOsO₃, Physical Review B 80, 161104 (2009).

[3] S. Calder, V. O. Garlea, D. F. McMorrow, M. D. Lumsden, M. B. Stone, J. C. Lang, J. W. Kim, J. A. Schlueter, Y. G. Shi, K. Yamaura, Y. S. Sun, Y. Tsujimoto, and A. D. Christianson, Magnetically Driven Metal-Insulator Transition in NaOsO₃, Physical Review Letters 108, 257209 (2012).

[4] J. G. Vale, S. Calder, C. Donnerer, D. Pincini, Y. G. Shi, Y. Tsujimoto, K. Yamaura, M. M. Sala, J. van den Brink, A. D. Christianson, and D. F. McMorrow, Evolution of the Magnetic Excitations in NaOsO₃ through its Metal-Insulator Transition, Physical Review Letters 120, 227203 (2018).