反位紊乱Ni1-xCoxCr2O4尖晶石的光学特性与磁学特性.pdfVIP

Trans. Nonferrous Met. Soc. China 27(2017) 863−867 Optical properties and magnetic properties of antisite-disordered Ni Co Cr O spinels 1−x x 2 4 Yu GAO, Hong CHANG, Qiang WU, Hong-yan WANG, Yan-bo PANG, Fang LIU, Hong-jing ZHU, Yue -hou YUN School of Physics, Inner Mongolia University, Hohhot 010021, China Received 29 February 2016; accepted 8 July 2016 Abstract: From the UV−Vis absorption spectra, the FT-IR absorption spectra and the Raman spectra, it is deduced that Co ions primarily occupy the tetrahedral (A) site, with a minor number of them entering into the octahedral (B) site in the Ni Co Cr O 1−x x 2 4 compounds. The origin of the position disorder of the Co ions is consistent with the similar ionic radii of the Co ion (0.65 Å) and the Cr ion (0.62 Å) at B site. The FT-IR peak at about 510 cm− 1 shifts towards high frequency side with the increasing cobalt content. It is resulted from the reduction of the cation−oxygen distance in the octahedron by the replacement of the Ni2+ with the Co2+ ions. The magnetic measurement shows that Curie temperatures (T ) are 75 and 90 K for the compounds with x=0.2 and 0.8, respectively. C Key words: spinel; antisite defect; electronic transition; optical properties; magnetic properties (B) site [4,7].