Charge and orbital orders and structural instability in high-pressure quadruple perovskite CeCuMn6O12. (23rd January 2018)

• Record Type: Journal Article
• Authors: Zhang, Lei; Matsushita, Yoshitaka; Katsuya, Yoshio; Tanaka, Masahiko; Yamaura, Kazunari; Belik, Alexei A
• Is Part Of: Journal of physics. Volume 30:Number 7(2018)
• Publication Date: 2018-01-23
• Subjects: high-pressure synthesis -- quadruple perovskite -- manganites; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aaa5e4
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: We prepared a quadruple perovskite CeCuMn6 O12 under high-pressure and high-temperature conditions at 6 GPa and about 1670 K and investigated its structural, magnetic and transport properties. CeCuMn6 O12 crystallizes in space group Im -3 above T CO = 297 K; below this temperature, it adopts space group R -3 with the 1:3 (Mn 4+ :Mn 3+ ) charge and orbital orders. Unusual compressed Mn 3+ O6 octahedra are realized in CeCuMn6 O12 similar to CaMn7 O12 with the − Q 3 Jahn–Teller distortion mode. Below about 90 K, structural instability takes place with phase separation and the appearance of competing phases; and below 70 K, two R -3 phases coexist. CeCuMn6 O12 exhibits a ferromagnetic-like transition below T C = 140 K, and it is a semiconductor with the magnetoresistance reaching about −40% at 140 K and 70 kOe. We argued that the valence of Ce is +3 in CeCuMn6 O12 with the Ce 3+ ( C u 2 + M n 2 3 + )( M n 3 3 + M n 4 + )O12 charge distribution in the charge-ordered R -3 phase and Ce 3+ ( C u 2 + M n 2 3 + )( M n 4 3 . 25 + )O12 in the charge-disordered Im -3 phase.