Suwei YAO
,
Zhaohui ZHAO
材料科学技术（英文）
The Fe3O4 films were prepared by in-situ oxidative hydrolysis on chitosan. The structures and characteristics of the prepared Fe3O4 films were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM), atom force microscopy (AFM), vibrating sample magnetometry (VSM) and thermogravimetric-differential thermal analysis (TG-DTA). The results show that, (1) the as-synthesized Fe3O4 films are pure Fe3O4 with cubic inverse spinel structure; (2) the network structured film can be obtained at lower temperature, and the compact particle film at higher temperature; (3) the prepared Fe3O4 films are super-paramagnetic, and the saturation magnetization is improved with increasing the reaction temperature, which is 49.03 emu/g at 80℃; (4) the temperature of phase transformation from F Fe3O4 to α-Fe2O3 is about 495℃. Besides, the formation mechanism of Fe3O4 film was also proposed.
关键词:
Fe3O4 film
,
film
,
In-situ
,
Oxidative
,
hydrolysis
Suwei YAO
,
Haixia WU
,
Weiguo ZHANG
,
Hongzhi WANG
材料科学技术（英文）
Granular CoxCu1-x alloy films were prepared by electrodeposition at room temperature directly onto semiconducting Si substrate. X-ray diffraction (XRD) revealed that the as-deposited films formed single phase metastable fcc alloy structure. The fcc lattice parameter α was found to decrease linearly with increasing Co concentration x in the studied range. The giant magnetoresistance (GMR) of the films was improved after annealing. Pure Co fcc diffraction peaks were observed in the diffractogram of the annealed sample, indicating phase separation occurred upon annealing. The optimal annealing temperature was 450℃. The maximum of magnetoresistance (MR) ratio 8.21% was obtained for the Co20Cu80 thin film after annealing at 450℃ for 1 h. The saturation field decreased upon annealing in the MR curves of Co20Cu81 film.
关键词:
Electrodeposition
,
巨磁电阻
,
电沉积
,
颗粒
