Mn₂TeO₆: a Distorted Inverse Trirutile Structure

Abstract

Inverse trirutile MnTeO was investigated using in situ neutron and X-ray powder diffraction between 700 °C and room temperature. When the temperature was decreased, a structural phase transition was observed around 400 °C, from a tetragonal (P4/mnm) to a monoclinic phase (P2/c), involving a doubling of the cell parameter along b. This complex monoclinic structure has been solved by combining electron, neutron, and synchrotron powder diffraction techniques at room temperature. It can be described as a distorted superstructure of the inverse trirutile structure, in which compressed and elongated MnO octahedra alternate with more regular TeO octahedra, forming a herringbone-like pattern. Rietveld refinements, carried out with symmetry-adapted modes, show that the structural transition, arguably of Jahn-Teller origin, is driven by a single primary mode.

BiMnTeO6 : A multiaxis Ising antiferromagnet

“…, which are strongly elongated, with 4 Mn-O distances ranging between ~1.87 Å and ~1.97 Å and two Mn-O distances larger than 2.1 Å (TableS.III). On the other hand, TeO 6 octahedra show very little distortion, confirming its "rigid compact unit" character also reported in Mn 2 TeO 6[32]. The monoclinic P2 1 /c distortion decomposes into three distortion modes of different symmetries, corresponding to the irreducible representations (irreps)  1 + , subgroups P-31c, C2/c and P2 1 /c, respectively.…”

“…Amongst tellurates, the prominent role of orbital ordering has been emphasized recently in Mn 2 TeO 6 , through the unusually complex set of structural and magnetic transitions observed [32], [44]. The relationship between spins and orbital ordering still remains to be understood however, as both crystal and magnetic structures could be incommensurate, like in CaMn 7 O 12 [45], pinpointing a delicate balance between Heisenberg exchanges and magnetic anisotropy in this compound.…”

Incorporation mechanism of tungsten in W-Fe-Cr-V-bearing rutile

“…The trirutile superstructure contains many members -a natural one such as tripuhyite (FeSbO 4 , Berlepsch et al 2003) and many more synthetic tantalates, tellurates, bismuthates, etc. (e.g., Kumada et al 1997, Matsubara et al 2017, Baral et al 2019. Hence, the rutile structure is as flexible in accommodating various cations as similar, simple structures based on ccp or hcp arrangement of the anions (spinels, perovskites, sesquioxides).…”

A Gas Sensor for Application as a Propane Leak Detector

“…These behaviors are due to the nature of the charge carrier that the semiconductor possesses. According to the literature, several semiconductor materials have been proposed for sensing applications, being some of them binary semiconductors (like NiO, CuO, WO 3 , and TiO 2 ) [11], perovskites (BaTiO 3 , NdCoO 3 , and ZnSnO 3 ) [12][13][14], spinels (AlCo 2 O 4 , NiFe 2 O 4 , and MgFe 2 O 4 ) [15][16][17], and trirutiles (MX 2 O 6 where M can be Ni, Co, or Cu and X is replaced by Sb or Ta [18,19], like NiSb 2 O 6 [20], CoTa 2 O 6 [21], and NiTa 2 O 6 [22]). Regardless of the semiconductor material used for the sensor, an electronic circuit with desirable features is required for signal adaptation: low cost, high functionality, fast response, high sensitivity, excellent repeatability, high resolution, and easy construction.…”