The present LDA + U calculations showed that neutral strontium vacancies at the SrO (100) surface could bring about large magnetic moments, locating mainly on the oxygen atoms surrounding the vacancies at the uppermost surface. 6.25% neutral strontium vacancies led to a ferromagnetic state of the surface. Carbon or nitrogen substitution for oxygen at the SrO (100) surface led to holes in C/N 2p states, which could also form local magnetic moments. There was a possible case that co-existence of neutral strontium vacancy and C/N substitution at the SrO (100) surface could weaken the ferromagnetism of the system, due to the charge compensation of C/N 2p electrons for O 2p holes.

Ferromagnetism Driven by Vacancies and C/N Substitution at SrO (100) Surface. F.Gao, J.Hu, J.Wang, C.Yang, H.Qin, M.Jiang: Solid State Sciences, 2011, 13[1], 126-30