Investigation Of Room Temperature Ferromagnetism In Oxides Of Copper

Dilute magnetic oxides semiconductor have been in forefront and significant branch of applied researches for various fields, which include photo-electro- magnetic materials, spintronics devices, and chemical technology, and so on. Here,we focus on the ferromagnetic origin and adjustment of dilute magnetic oxides semiconductor through oxides of copper. We discussed the effect of vacuum annealing, annealing temperature, the ratio of composites and vacancy concentration to the room ferromagnetism of the samples. The main results are as follows:1、Flowerlike Cu O nanostructures were prepared by co-precipitation and annealing method. The morphology and ferromagnetism of the samples were studied by changing annealing temperature and annealing time. The results indicate that we can change the crystal size of the samples by changing the annealing temperature and annealing time. Thus, the ferromagnetic of the samples can also be tuned. The results of vacuum annealing indicates that the ferromagnetism of the samples is related to oxygen vacancy at the surface or interface of nanoparticle.2、The Cu2O/Cu and C u2O/Cu O nanoparticle composites were fabricated by heating a mixture of copper nitrate with different amounts of glycine. Their magnetic properties were studied by ad justing the ratio to Cu2 O and Cu or Cu2 O and Cu O. The results indicate that the amount of interface reach to the maximum when the ratio to two phases is close to equal. Due to the competition of two phase, amount of Cu vacancy appeared at the surface and the sample behave the highest saturation magnetization at this time, which indicates that the ferromagnetism is related to Cu vacancy. A bound magnetic polaron model is applied to explain the origins of ferromagnetism. Besides, the Ms of the composites can be tuned by adjusting the ratio of two phases.3、We deposited the Cu O thin film using a magnetron sputtering system. Large amounts of artificial vacancies were made by argon ions irradiation Cu O thin film. We find that the Cu vacancies concentration will increase when the irradiation dose increase. Meanwhile, due to the phase changing, the saturation magnetization of sample will be improved. Therefore, we can modulate the Cu vacancies concentration by control the irradiation dose, and further modulate the ferromagnetism of samples.