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Title: Local symmetry lowering in CdMn{sub 2}O{sub 4} spinel

This work presents an atomic scale study of the electric field gradient (EFG) in the tetragonally distorted CdMn{sub 2}O{sub 4} spinel manganite. The EFG temperature dependence at the Cd and Mn sites was followed via perturbed angular correlation measurements with the {sup 111}In and {sup 111m}Cd probes, from 873 down to 12 K at Isolde-CERN. The results show that in the 12–600 K temperature range, a single Jahn-Teller distorted local phase exists. However above 100 K, a dynamic lattice distortion, evidenced by time dependent EFG fluctuations, sets in suggesting a structural instability. Above 600 K, a local MnO{sub 6} octahedra with relaxed Jahn-Teller distortions emerge and grow in the low temperature matrix, although no macroscopic tetragonal to cubic phase transition was observed.
Authors:
;  [1] ;  [2] ; ;  [1] ; ;  [3] ;  [4]
  1. CFNUL - Centro de Física Nuclear, Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal)
  2. (Portugal)
  3. IFIMUP and IN-Institute of Nanoscience and Nanotechnology, Departamento de Física e Astronomia da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal)
  4. C2TN, Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, 2695-066 Bobadela LRS (Portugal)
Publication Date:
OSTI Identifier:
22402776
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 22; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CADMIUM 111; CERN; ELECTRIC FIELDS; FLUCTUATIONS; INDIUM 111; INSTABILITY; JAHN-TELLER EFFECT; MANGANESE OXIDES; PERTURBED ANGULAR CORRELATION; PHASE TRANSFORMATIONS; PROBES; SPINELS; SYMMETRY; TEMPERATURE DEPENDENCE; TIME DEPENDENCE