Raman Spectra and Magnetic Property Analysis of Nd-Doped ZnO Thin Films

The present investigation is a detailed study aiming to understand the origin of the ferromagnetism of the well-characterized Nd-doped ZnO films. Raman scattering shows that the E 2 phonon line of Zn 1-x Nd x O ($x = 0$, 0.05, 0.10, and 0.15) is broadened asymmetrically and shifts to a lower frequency, suggesting microscopic structural disorder induced by Nd 3+ substitutions. Zn 1-x Nd x O films exhibit room-temperature ferromagnetism with a Curie temperature higher than 350 K. In addition, the films revealed magnetic anisotropy with higher magnetization in 3 kOe when the field was applied in the perpendicular direction to the sample surface than when applied in an in-plane direction.