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Phase coexistence in annealed CaMn7O12 |
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| Authors: | Rados?aw Przenios?o Wouter van BeekIzabela Sosnowska |
| Institution: | a Institut Laue-Langevin, 6 rue Jules Horowitz, BP-156X 38 042 Grenoble Cedex 9, France b Institute of Experimental Physics, Warsaw University, Ho?a 69, PL-00 681 Warsaw, Poland c Swiss-Norwegian Beamlines at E.S.R.F., BP 220, 38 043 Grenoble, France |
| Abstract: | The structural phase transition in annealed CaMn7O12 has been investigated by using high resolution synchrotron radiation powder diffraction. There is a phase coexistence phenomenon: two different crystallographic phases coexist in the material between 410 and 458 K. The first one is trigonal and it has a charge ordering (CO) of the Mn3+ and Mn4+ ions, while the second one is cubic and charge delocalized (CD). The volume fraction of the CD phase increases with temperature from 22% at 418 K up to 100% at 468 K. Both phases have domains of at least 150 nm at each temperature. The annealing of CaMn7O12 relaxed a part of the strains in the lattice, but did not influence the phase coexistence phenomenon. |
| Keywords: | 61 10 &minus i 61 12 &minus q 65 40 &minus b 75 30 Vn |
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