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Crystal Structure Phase Transitions in the Perovskites A(Cu 1− x Mn x )Mn 4 O 12 (A = Na + , Ca 2+ , Y 3+ , La 3+ )
Author(s) -
Troyanchuk I. O.,
Balyko L. V.,
Bashkirov L. A.
Publication year - 1986
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.2170210603
Subject(s) - crystallography , monoclinic crystal system , octahedron , crystal structure , jahn–teller effect , x ray crystallography , manganese , phase (matter) , symmetry (geometry) , trigonal crystal system , crystal (programming language) , chemistry , unit (ring theory) , diffraction , materials science , physics , ion , geometry , programming language , mathematics , mathematics education , organic chemistry , computer science , optics
Abstract X‐Ray diffraction and neutronographical studies on the crystal structure of the perovskitelike compounds A(Cu 1− x Mn x )Mn 4 O 12 have been undertaken. It has been shown that the samples with 50% of Mn 3+ in the octahedral sites have a cubic unit cell, while the samples with higher Mn 3+ composition may have a monoclinic or rhombohedral unit cell. The temperature increase raises the symmetry to the cubic one. The concentration ranges with different symmetry type have been determined. The lowering of the symmetry of the unit cell is due to the cooperative Jahn‐Teller effect.