High pressure synthesis and physical properties of novel functional perovskite LnBaMn2O6
Zih-Mei Hong1, Fernando Pomiro2, Mark Senn2, Wei-Tin Chen3,4*
1Department of Chemistry, Fu Jen Catholic University, New Taipei City, Taiwan
2Department of Chemistry, University of Warwick, Coventry, UK
3Center for Condensed Matter Sciences, National Taiwan University, Taipei City, Taiwan
4The Center of Atomic Initiative for New Materials, National Taiwan University, Taipei City, Taiwan
* Presenter:Wei-Tin Chen, email:weitinchen@ntu.edu.tw
The perovskite manganite families were extensively investigated due to their rich magnetic and electric properties such as colossal magnetoresistance and metal-insulator transitions with charge and/or orbital orderings. It was reported that the degree of cation ordering in double perovskites LnBaMn2O6 (Ln = lanthanoids) plays crucial rule to affect their physical properties. Recent research showed that SmBaMn2O6 exhibits ferroelectricity owing to A-site cation ordering and also B-site Mn3+/Mn4+ charge and orbital ordering. [1] In order to further investigate the coupling of A- and B-site ordering in manganite double perovskite family and to prepare novel material with multiferroic property, here cerium was introduced by means of high-pressure high-temperature synthesis techniques with various conditions. The preliminary x-ray powder diffraction results indicate that the synthesised materials are single phase and crystalised in Pm-3m cubic space group. The magnetic susceptibility of the materials, however, are shown to be distinct according to synthesis conditions. A clear magnetic transition temperature TN~40 K was exhibited in the sample synthesised at lower pressure, while an additional magnetic feature ~230 K from unknown origin was observed in the sample synthesised at higher pressure. Further discussion on A- and B-site ordering and the structure-property relationship in LnBaMn2O6 series will be presented.

[1] H. Sagayama, S. Toyoda, K. Sugimoto, Y. Maeda, S. Yamada and T. Arima, PRB, 90, 241113, 2014.

Keywords: high pressure synthesis, multiferroic, crystal structure, charge ordering