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(Ca0.5Mn0.5)2MnTeO6 - An Anomalously Stable High-Pressure Double Perovskite
Azizah Almadhi1, Kunlang Ji1, Sean D Injac1
1Centre for Science at Extreme Conditions (CSEC) and School of Chemistry, University of Edinburgh, Peter Guthrie Tait Road, EH9 3FD, Edinburgh, UK.
Abstract:
High pressure high temperature treatments of the composition CaMnMnTeO6 are found to yield only an A2BB'O6-type double perovskite (Ca0.5Mn0.5)2MnTeO6, rather than a AA'BB'O6 double double perovskite with A- and B- site cation order as found in analogs CaMnMnReO6 and CaMnMnWO6 with similar cation sizes. Double perovskite (Ca0.5Mn0.5)2MnTeO6 adopts a monoclinic structure in space group P21/n with a framework of highly tilted MnO6 and TeO6 octahedra enclosing disordered Ca2+ and Mn2+ cations. Magnetic measurements show that (Ca0.5Mn0.5)2MnTeO6 is a highly frustrated spin glass with a freezing transition at 5 K, and no long-range spin order is apparent by neutron diffraction at 1.6 K.
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