Influence of oxygen non-stoichiometry on physical properties of NdSr_2Mn_2O_(7±δ)

作     者：A.M.Yankin A.V.Fetisov O.M.Fedorova S.A.Uporov V.Ya.Mitrofanov 

作者机构：Laboratory of Static and Kinetics of Processes Institute of Metallurgy of Ural Branсh of Russian Academy of Science Amundsen St. 101 Ekaterinburg 620016 Russia 

出 版 物：《Journal of Rare Earths》 (稀土学报（英文版）)

年 卷 期：2015年第33卷第3期

页      面：282-288页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 0703[理学-化学] 070301[理学-无机化学] 

基　　金：Project supported by Russian Foundation for Basic Research(12-03-00042) 

主　　题：oxygen stoichiometry gravimetric analysis electroconductivity magnetic properties rare earths 

摘      要：Nd Sr2Mn2O7＋δ compounds were synthesized by ceramic method under three different cooling conditions. The Nd Sr2Mn2O7＋δ samples were characterized by powder X-ray diffraction（XRD）. Oxygen non-stoichiometry data for the studied powders were determined by using gravimetric and X-ray photoelectron spectroscopy（XPS） methods. The correlation of cooling method and oxygen as non-stoichiometry was established. The electroconductivity in samples was studied by using four-point probe method, and the strong correlation with non-stoichiometry was found out. Magnetization measurements were carried out. It was found that the magnetic and transport properties of the samples were also influenced by oxygen non-stoichiometry. The evolution of the magnetic properties could be explained by the formation of magnetic clusters in the vicinity of oxygen vacancies（OV） and strong competition between the superexchange and double exchange interactions.