Probing local symmetry changes in LaMnO3.12 rhombohedric-orthorhombic phase transition

A.M.L. Lopes 2,5Joao P. Araujo 3E. Rita 1,5J. G. Correia 1,5V. S. Amaral 2Yuan Li 2J. M. Vieira 4R. Suryanarayanan 6ISOLDE Collaboration 5

1. Instituto Técnológico Nuclear (ITN), Sacavém 2686, Portugal
2. Universidade de Aveiro, Departamento de Fisica and CICECO (UA), Campus de Santiago, Aveiro 3810-193, Portugal
3. Departamento de Fisica and IFIMUP, Universidade do Porto (UP), Rua do Campo Alegre, 687, Porto 4169-007, Portugal
4. Universidade de Aveiro, Departamento de Engenharia Cerâmica e do Vidro and CICECO (UA), Campus de Santiago, Aveiro 3810-193, Portugal
5. European Centre for Nuclear Research (CERN), Geneva CH1211, Switzerland
6. Laboratoire de Physico-Chimie de l'Etat Solide, bât 414, Université Paris-Sud, Orsay 91405, France

Abstract

It is well established that the LaMnO3+δ system presents a rich variety of structural (rhombohedral, orthorhombic) and magnetic (antiferromagnetic or ferromagnetic) phase as a function of the oxygen content (δ) or as a function of temperature (T). To deeply understand the Rh-Orth phase transition we combined High Resolution TEM, Perturbed Angular Correlation (PAC) and X-ray powder diffraction (XRD) studies in the temperature range 10-323 K in polycrystalline sample prepared by solid state reaction method. From the PAC signal we determined the Electrical Field Gradient (EFG) parameters which are sensitive to the charge distribution around the probe vicinity and therefore to the local symmetry of the crystal. In the 10-323 K temperature range two different EFG were measured revealing two different local environments. Phase coexistence was found in large temperature range. The measured EFG were assigned to the Rh/Orth local environment. Within the same temperature range the ED-HRTEM and bright/dark field imaging results showed the existence of laths and twinning domains of different crystalline simmetry. This data and the complementary 2 line shifts observed by XRD suggest a displacive martensite like Rh-Orth phase transition.

Legal notice
  • Legal notice:

    Copyright (c) Pielaszek Research, all rights reserved.
    The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
    In every case, proper references including Author(s) name(s) and URL of this webpage: http://science24.com/paper/986 must be provided.

 

Related papers
  1. Numerical analysis of multi-phase flow in the sublimation growth of SiC crystal by a 2-D incompressible kinetic model
  2. Influence of surface pre-treatment on the pore growth of nanoporous alumina at room temperature
  3. Structural and magnetic characterization of thin films prepared by ion beam deposition
  4. Transport properties in the pseudobinary Er5Si4 compound
  5. Transition from ferro to mictomagnetism in rich FexAl1-x alloys. A magnetoresistivity study.
  6. Electromigration-driven resistance switching in magnetic and non-magnetic tunnel junctions
  7. Local Probe Studies of high-Tc Superconductors and CMR Oxides Using Radioactives Isotopes
  8. Structural and magnetic study of self- doped La1-x-yCaxVacyMnO3
  9. Charge-ordering and magnetoelastic coupling effects on the magnetocaloric properties of manganites
  10. Magnetic nonextensivity on CMR manganites

Presentation: poster at E-MRS Fall Meeting 2003, Symposium D, by Armandina L. Lopes
See On-line Journal of E-MRS Fall Meeting 2003

Submitted: 2003-05-28 03:40
Revised:   2009-06-08 12:55
Google
 
Web science24.com
© 1998-2021 pielaszek research, all rights reserved Powered by the Conference Engine