Abstract
The magnetic structure and the origin of band gap opening for Ba2CuOsO6 were investigated by exploring the spin exchange interactions and employing the spin–orbit coupling effect. It revealed that the double-perovskite Ba2CuOsO6, composed of the 3d (Cu2+) and 5d (Os6+) transition metal magnetic ions is magnetic insulator. The magnetic susceptibilities of Ba2CuOsO6 obey the Curie–Weiss law, with an estimated Weiss temperature of −13.3 K, indicating AFM ordering. From the density functional theory approach, it is demonstrated that the spin exchange interaction between Cu ions plays a major role in exhibiting an antiferromagnetic behavior in the Ba2CuOsO6 system. An important factor to understand regarding the insulating behavior on Ba2CuOsO6 is the structural distortion shape of OsO6 octahedron, which should be closely connected with the ionic size of the A-site ion. Since the d-block of Os6+ (d2) ions of Ba2CuOsO6 is split into four states (xy < xz, yz < x2–y2 < z2), the crucial key is separation of doubly degenerated xz and yz levels to describe the magnetic insulating states of Ba2CuOsO6. By orbital symmetry breaking, caused by the spin–orbit coupling, the t2g level of Os6+ (d2) ions is separated into three sublevels. Two electrons of Os6+ (d2) ions occupy two levels of the three spin–orbit-coupled levels. Since Ba2CuOsO6 is a strongly correlated system, and the Os atom belongs to the heavy element group, one speculates that it is necessary to take into account both electron correlation and the spin–orbit coupling effect in describing the magnetic insulating states of Ba2CuOsO6.
Highlights
Introduction iationsVarious osmium oxide compounds exhibit attractive magnetic and electronic phenomena developed from their electron correlation effects, such as the ferromagnetic gapped state in Ba2 NiOsO6 [1], the singlet ground-state excitonic magnetism in Y2 OsO7 [2,3,4], the spindriven metal to insulator transition in Pb2 CaOsO6 [5], and the unusual superconductivity in AOsO6 (A = Cs, Rb, and K) [6].The solid-state osmium oxides are noteworthy for the following two reasons
Various mechanisms for explaining the band gap opening for solid-state osmium oxide compounds have been extensively considered, such as the Mott-type mechanism, the d-level splitting pattern caused by the electron correlation effect, the Slater-type mechanism, and the orbital symmetry breaking mechanism, driven by the spin–orbit coupling (SOC)
The magnetic structure and the origin of the band gap opening for Ba2 CuOsO6 are investigated by exploring the spin exchange interactions and analyzing the spin–orbit coupling effect
Summary
CuOsO6,6 ,where whereblue bluepolyhedra polyhedraand andyellow yellowpolyhedra polyhedraand andblue, blue, yellow, represent CuO. Perspective view of (a) ac plane and (b) ab plane. REVIEW of 14 centered Cu4Os4 cube in which the Ba ion is connected by 4 Oax and 8 Oeq atoms. Ba-centered Cu4 Os4 cube in which the Ba ion is connected by 4 Oax and 8 Oeq atoms. Distortion, associated with the electron configuration of the Cu2+ (d9) ion in each CuO6. Cu-Oax6bonds along z2 orbital direction (crystallographic c direction) and four short equatorial Cu-O bonds in the x2–y2 orbital locating plane (the crystallographic ab plane). In each OsO6 octahedron, the (t2g) electron configuration of the Os6+ ion exhibits a weak Jahn–Teller distortion, associated with spatial extension of 5d orbital (see Scheme 1). OsO6 The magnetic explained by the aspect of their orbital interactions and their spin exchange interactions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
