Room temperature ferromagnetism in un-doped amorphous HfO2 nano-helix arrays*
Xie Qian, Wang Wei-Peng, Xie Zheng, Zhan Peng, Li Zheng-Cao, Zhang Zheng-Jun†
       
(a) PL spectra and peak fit of the flat film sample; (b) PL spectra and peak fit of the four spiral sample; (c) peak area proportions of the Gaussian peaks,the inset shows the total PL peak area of each sample; (d) M s and the peak 1 area proportion versus the sample morphology.