High pressure synthesis and physical properties of novel functional perovskite LnBaMn₂O₆

Zih-Mei Hong¹, Fernando Pomiro², Mark Senn², Wei-Tin Chen^3,4*

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 T_N~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