Enhancement of room-temperature ferromagnetism in manganese oxide thin films grown on Nb:SrTiO_3 substrates

摘要

In this paper, α-Mn_2O_3 thin films were fabricated by plasma-assisted molecular beam epitaxy on SrTiO_3 and Nb:SrTiO_3, respectively. The grown samples showed room temperature ferromagnetism (RFM) properties. All the experimental results manifested that the RFM properties in undoped thin films were induced by oxygen vacancies formed during the growth process. Even more, the ferromagnetism of thin films grown on Nb:SrTiO_3 were enhanced, and these results confirmed the fact that oxygen vacancies induced ferromagnetism. That is to say, more oxygen vacancies result the more unpaired electrons induced prominent abnormal spin causing ferromagnetism.