Ferromagnetism analysis of Mn-doped CuO thin films

Mn (6.6–29.8%)-doped CuO thin film fabricated on a thermally oxidized silicon substrate by radio-frequency magnetron sputtering has been reported. The films were structurally characterized using x-ray diffraction with Rietveld refinement. The analysis indicates that Mn uniformly substituted at the Cu position in the CuO lattice. 5% cation vacancies were detected at the Cu sites and are supposed to be responsible for the p-type electrical conduction of Cu1−xMnxO films. No evidence for large scale Mn aggregation was found in the composition range analyzed. The origin of ferromagnetism was analyzed in the context of competition among several interactions among Mn and Cu ions. A chain model was developed to simulate the ferromagnetic behavior with the random Mn distribution in the samples. The consistency between simulation and experiment strongly indicates that the ferromagnetism mainly arises from the super-exchange interactions of Mn–O–Cu–O–Mn coupling in the [] chain and Mn–O–Mn coupling contributes to the antiferromagnetism.