High-pressure synthesis, crystal structures, and magnetic properties of 5d double-perovskite oxides Ca2MgOsO6 and Sr2MgOsO6.
Double-perovskite oxides Ca2MgOsO6 and Sr2MgOsO6 have been synthesized under high-pressure and high-temperature conditions (6 GPa and 1500 °C). Their crystal structures and magnetic properties were studied by a synchrotron X-ray diffraction experiment and by magnetic susceptibility, specific heat, isothermal magnetization, and electrical resistivity measurements. Ca2MgOsO6 and Sr2MgOsO6 crystallized in monoclinic (P21/n) and tetragonal (I4/m) double-perovskite structures, respectively; the degree of order of the Os and Mg arrangement was 96% or higher. Although Ca2MgOsO6 and Sr2MgOsO6 are isoelectric, a magnetic-glass transition was observed for Ca2MgOsO6 at 19 K, while Sr2MgOsO6 showed an antiferromagnetic transition at 110 K. The antiferromagnetic-transition temperature is the highest in the family. A first-principles density functional approach revealed that Ca2MgOsO6 and Sr2MgOsO6 are likely to be antiferromagnetic Mott insulators in which the band gaps open, with Coulomb correlations of ∼1.8-3.0 eV. These compounds offer a better opportunity for the clarification of the basis of 5d magnetic sublattices, with regard to the possible use of perovskite-related oxides in multifunctional devices. The double-perovskite oxides Ca2MgOsO6 and Sr2MgOsO6 are likely to be Mott insulators with a magnetic-glass (MG) transition at ∼19 K and an antiferromagnetic (AFM) transition at ∼110 K, respectively. This AFM transition temperature is the highest among double-perovskite oxides containing single magnetic sublattices. Thus, these compounds offer valuable opportunities for studying the magnetic nature of 5d perovskite-related oxides, with regard to their possible use in multifunctional devices.
†Superconducting Properties Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.|‡Graduate School of Chemical Sciences and Engineering, Hokkaido University, North 10 West 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
Yahua
Y
Yuan
†Superconducting Properties Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.|‡Graduate School of Chemical Sciences and Engineering, Hokkaido University, North 10 West 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
Hai L
HL
Feng
§Condensed Matter Physics Research Center, Butwal, Rupandehi, Nepal.
Madhav Prasad
MP
Ghimire
∇Materials Analysis Station, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
Yoshitaka
Y
Matsushita
⊥Materials Processing Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
Yoshihiro
Y
Tsujimoto
†Superconducting Properties Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.|‡Graduate School of Chemical Sciences and Engineering, Hokkaido University, North 10 West 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
Jianfeng
J
He
#Synchrotron X-ray Station at SPring-8, National Institute for Materials Science, Kohto 1-1-1, Sayo-cho, Hyogo 679-5148, Japan.
Masahiko
M
Tanaka
#Synchrotron X-ray Station at SPring-8, National Institute for Materials Science, Kohto 1-1-1, Sayo-cho, Hyogo 679-5148, Japan.
Yoshio
Y
Katsuya
†Superconducting Properties Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.|‡Graduate School of Chemical Sciences and Engineering, Hokkaido University, North 10 West 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
Kazunari
K
Yamaura