Xue Hou

Significant room temperature ferromagnetism in PAA thin films

Room-temperature ferromagnetism has been observed in Porous Anodic Aluminum (PAA) thin films, with an out-of-plane saturation magnetization of 60 emu cm−3. The significant out-of-plane saturation magnetization is associated with the porous structure of the film. As there were no magnetic impurities present, the origin of the ferromagnetism is most likely due to exchange interactions between localized electron spin moments resulting from oxygen vacancies in the films. A similar hysteretic behavior is observed in porous thin films of nonmagnetic TiO2 and ZnO. This suggests that ferromagnetism may be a universal characteristic of porous thin films of nonmagnetic metal oxides. Our present results suggest a promising direction for research in spintronic devices.

Optical and magnetic properties of PAA@Fe nanocomposite films

A simple method to fabricate porous anodic alumina films embedded with Fe is reported. The films exhibit vivid structural colors and magnetic properties after being synthesized by an ac electrodeposition method. The optical properties of the samples can be effectively tuned by varying the oxidation time of aluminum. The coercivity mechanism of the Fe nanowires in our case is consistent with fanning reversal mode. PAA@Fe films can be used in many areas including decoration, display and multifunctional anti-counterfeiting applications.