The Open Condensed Matter Physics Journal
2009, 2 : 19-24Published online 2009 May 5. DOI: 10.2174/1874186X00902010019
Publisher ID: TOCMPJ-2-19
RESEARCH ARTICLE
Anomalous Structural Change of Layered Perovskite Manganites La SrMnO
1
Department of Physics, Beijing University of Science and Technology, Beijing 100083, China
2 Department of Physics, Capital Normal University, Beijing 100037, China
3 Beijing Synchrotron Radiation Laboratory, Institute of High Energy Physics, Chinese Academy of Science, Beijing, 100049, China
4 Department of Material Physics and Chemistry, Beijing University of Science and Technology, Beijing 100083, China
5 Institute of Physics, Chinese Academy of Sciences, P.O.Box 603, Beijing 100080, China
6 Department of Mathematics, University of Texas-Pan American, Edinburg, TX 78541, USA
7 Department of Engineering Science and Materials, University of Puerto Rico at Mayaguez, PR 00681-9044, USA
* Address correspondence to this author at the Department of Physics, Beijing University of Science and Technology, Beijing 100083, China; E-mail: ylibp@hotmail.com
2 Department of Physics, Capital Normal University, Beijing 100037, China
3 Beijing Synchrotron Radiation Laboratory, Institute of High Energy Physics, Chinese Academy of Science, Beijing, 100049, China
4 Department of Material Physics and Chemistry, Beijing University of Science and Technology, Beijing 100083, China
5 Institute of Physics, Chinese Academy of Sciences, P.O.Box 603, Beijing 100080, China
6 Department of Mathematics, University of Texas-Pan American, Edinburg, TX 78541, USA
7 Department of Engineering Science and Materials, University of Puerto Rico at Mayaguez, PR 00681-9044, USA
* Address correspondence to this author at the Department of Physics, Beijing University of Science and Technology, Beijing 100083, China; E-mail: ylibp@hotmail.com
ABSTRACT
The temperature-dependent structural changes were investigated by using the X-ray diffraction and the Extended X-ray absorption fine spectroscopy (EXAFS) for layered perovskite manganites La2-2xSr1+2xMn2O7 (x=0.33 and 0.4). The anomalous changes of Mn-O bond length and Jahn-Teller (J-T) distortion of MnO6 octahedron were observed, corresponding to ferromagnetic transition temperature (~ 120 K). Around the temperature of 2D short-range magnetic ordering (~ 235 K), there occurs an anomaly of the Jahn-Teller distortions of MnO6. These results indicate that magnetic properties of perovskite manganites La2-2xSr1+2xMn2O7 depend heavily on their microstructure change. The orbital state occupancy is involved in the observed Mn-O bond change.