The magnetic ordering in high magnetoresistance Mn-doped ZnO thin films
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
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AbstractWe studied the nature of magnetic ordering in Mn-doped ZnO thin films that exhibited ferromagnetism at 300 K and superparamagnetism at 5 K. We directly inter-related the magnetisation and magnetoresistance by invoking the polaronpercolation theory and variable range of hopping conduction below the metal-to-insulator transition. By obtaining a qualitative agreement between these two models, we attribute the ferromagnetism to the s-d exchange-induced spin splitting that was indicated by large positive magnetoresistance (∼40 %). Low temperature superparamagnetism was attributed to the localization of carriers and non-interacting polaron clusters. This analysis can assist in understanding the presence or absence of ferromagnetism in doped/un-doped ZnO.
CitationThe magnetic ordering in high magnetoresistance Mn-doped ZnO thin films 2016, 6 (3):035019 AIP Advances
SponsorsThe authors wish to thank KAUST for the financial support. Synchrotron studies were carried out at the SSRL, a Directorate of SLAC and an Office of Science User Facility operated for the US DOE Office of Science by Stanford University. J.S.L. acknowledges partial funding from the Global Research Laboratory program of the Korean Ministry of Education, Science, and Technology (MEST). The authors also thank Dr. Paul R Edwards and Prof. Robert W Martin for using EPMA facilities at University of Strathclyde.