Facile Synthesis, Magnetic and Electric Characterization of Mixed Valence La0.75K0.25AMnTiO6 (A = Sr and Ba) Perovskites
Facile Synthesis, Magnetic and Electric Characterization of Mixed Valence La0.75K0.25AMnTiO6 (A = Sr and Ba) Perovskites
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混合价 La0.75K0.25AMnTiO6（A = Sr 和 Ba）钙钛矿的简易合成及磁电表征
DOI：
10.1021/acs.inorgchem.7b01337
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发表时间：
2017
影响因子：
4.6
通讯作者：
Fuqiang Huang
中科院分区：
文献类型：
--
作者：
Ganghua Zhang;Haijie Chen;Zheming Gu;Peizhi Zhang;Tao Zeng;Fuqiang Huang
采用温和水热法合成了一系列新的混合价钙钛矿La0.75K0.25AMnTiO6 （A = Sr和Ba）纳米立方体。粉末x射线衍射（XRD）分析表明，La0.75K0.25AMnTiO6的晶体结构为a位或b位随机排列的正交对称（空间群Pbnm）结构。通过ICP、SEM和EDS分析证实了产物的相纯度，XPS结果确定b位金属原子的氧化态为+4 （Ti）和+3/+4 （Mn）。两种样品均存在软铁磁行为。La0.75K0.25SrMnTiO6的居里点TC高达309 K， La0.75K0.25BaMnTiO6的居里点TC高达217 K。在高温区可以观察到Griffiths相，这与近程铁磁团簇的存在引起的磁不均匀性有关。电阻率测量表明，由于Mn3+-O-Mn4+与Ti4+掺杂的双重交换作用被稀释，通过变跳程（VRH）可以更好地描述样品的半导体特性。
A new series of mixed valence perovskites, La0.75K0.25AMnTiO6 (A = Sr and Ba) nanocubes, have been synthesized by a mild hydrothermal route. From powder X-ray diffraction (XRD) analysis, the crystal structure of La0.75K0.25AMnTiO6 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 TC has been detected as high as 309 K in La0.75K0.25SrMnTiO6 and 217 K in La0.75K0.25BaMnTiO6. 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.