Synthesis, crystal structure, and properties of KSbO3-type Bi3Mn1.9Te1.1O11

Single crystals of Bi3Mn1.9Te1.1O11 were prepared from NaCl+KCl flux. This compound adopts KSbO3-type crystal structure as evidenced by electron and single crystal X-ray diffraction analysis. The three-dimensional channel structure is formed by corner-sharing octahedral (Mn0.63Te0.37)2O10 dimers and two identical (Bi1)4(Bi2)2 interpenetrating lattices. The intra-dimer Mn/Te–Mn/Te distances in Bi3Mn1.9Te1.1O11 are short and are consistent with weak metal–metal interactions. The mixed oxidation state of manganese and the edge-sharing octahedral features are confirmed by X-ray near edge absorption spectroscopy measurements, which indicate Bi3(MnIII1.1MnIV0.8)TeVI1.1O11 with 57.7% Mn3+ and 42.3% Mn4+. The partial substitution of Te for Mn perturbs long-range magnetic interactions, thereby destroying the ferromagnetic ordering found in Bi3Mn3O11 (TC=150 K).

Single crystal of Bi3Mn1.9Te1.1O11 was grown from NaCl+KCl binary flux, suggesting that the high pressure Bi3Mn3O11 phase can be stabilized by partial substitution of Mn by Te at ambient pressure. Bi3Mn1.9Te1.1O11 adopts a typical three dimensional KSbO3-type crystal structure with three interpenetrating lattices and weak intra-dimmer metal–metal interaction caused by the d electrons of Mn. The edge-shared (Mn0.63Te0.37)2O10 octahedral dimer and mixed oxidation state of manganese (Bi3(MnIII1.1MnIV0.8)TeVI1.1O11 with 57.7% Mn3+ and 42.3% Mn4+) features were evidenced by X-ray absorption near edge spectroscopy. Compared with Bi3Mn3O11, the Te substituted Bi3Mn1.9Te1.1O11 relaxes the crystal structure, but destroys the long-range magnetic ordering and gives short-range magnetic ordering below 5 K.Figure optionsDownload as PowerPoint slideHighlights
► High pressure Bi3Mn3O11 is stabilized by partial Te substitution at ambient pressure.
► New KSbO3-type Bi3Mn1.9Te1.1O11 single crystal was grown from binary flux.
► The presence of mixed oxidation state of manganese is evidenced by XANES study.
► The Te-substitution destroys the long-range magnetic ordering and relaxes the structure.