Ferromagnetism in polycrystalline Cr-doped ZnO films: Experiment and theory

Room-temperature ferromagnetism is found in polycrystalline CrxZn1−xO ( 0 ≤ x ≤ 0.091 ) films prepared by magnetron sputtering. The saturated magnetization is ∼ 0.58 μB/Cr with x = 0.012 , and decreases with increased Cr dopant. The Curie temperatures of the samples are above 400 K. First principles calculations based on density functional theory predict that the electrons of Cr-doped ZnO films at Fermi level are 100% spin polarized when two Zn sites are substituted by Cr atoms in the nearest neighbour configuration. The spin polarized carriers and the p–d hybridization between Cr and its four neighbouring O atoms are responsible for observed ferromagnetism.