Facile Synthesis, Magnetic and Electric Characterization of Mixed Valence La0.75K0.25AMnTiO6 (A = Sr and Ba) Perovskites

Ganghua Zhang; Haijie Chen; Zheming Gu; Peizhi Zhang; Tao Zeng; Fuqiang Huang

doi:10.1021/acs.inorgchem.7b01337

Facile Synthesis, Magnetic and Electric Characterization of Mixed Valence La_0.75K_0.25AMnTiO₆ (A = Sr and Ba) Perovskites

Inorg Chem. 2017 Sep 5;56(17):10404-10411. doi: 10.1021/acs.inorgchem.7b01337. Epub 2017 Aug 17.

Authors

Ganghua Zhang^{1

2}, Haijie Chen², Zheming Gu¹, Peizhi Zhang³, Tao Zeng¹, Fuqiang Huang²

Affiliations

¹ Shanghai Key Laboratory of Engineering Materials Application and Evaluation, Shanghai Research Institute of Materials , Shanghai 200437, P. R. China.
² State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences , Shanghai 200050, P. R. China.
³ The Ministry of Powder Materials, Shanghai Research Institute of Materials , Shanghai 200437, P. R. China.

PMID: 28816450
DOI: 10.1021/acs.inorgchem.7b01337

Abstract

A new series of mixed valence perovskites, La_0.75K_0.25AMnTiO₆ (A = Sr and Ba) nanocubes, have been synthesized by a mild hydrothermal route. From powder X-ray diffraction (XRD) analysis, the crystal structure of La_0.75K_0.25AMnTiO₆ was solved as the orthorhombic symmetry (space group Pbnm) with a random A-site or B-site arrangement. The phase purity of the products was confirmed by ICP, SEM, and EDS analyses, and the oxidation states of the B-site metal atoms were determined to be +4 for Ti and +3/+4 for Mn from XPS results. The soft ferromagnetic behavior is present in both samples. The Curie point T_C has been detected as high as 309 K in La_0.75K_0.25SrMnTiO₆ and 217 K in La_0.75K_0.25BaMnTiO₆. A Griffiths phase can be observed at the high temperature region, which is related to the magnetic inhomogeneity induced by the existence of short-range ferromagnetic clusters. The resistivity measurements indicate that the semiconducting properties of the samples can be depicted better by variable range hopping (VRH) due to a diluted double-exchange interaction of Mn³⁺-O-Mn⁴⁺ with Ti⁴⁺ doping.