Influence of sputtering atmosphere on the structural and magnetic properties of (Bi1−xNdx)FeO3 thin films

(Bi1−xNdx)FeO3 (BNF, x = 0.075 and 0.125) thin films were grown on Si(100) substrates by radio frequency magnetron sputtering with various deposition atmospheres. It was found that the sputtering atmosphere has affected the phase structure, surface morphology and magnetic properties of BNF thin films. X-ray diffraction revealed that the BNF thin films exhibit highly (012)-orientation crystallization when the sputtering atmosphere is nitrogen (N2), while, the inter-phase Bi2O3 was observed when the sputtering atmosphere is the mixture of argon and oxygen (Ar/O2). Compared with the thin film deposited in Ar/O2, the films sputtered in N2 showed a smoother surface and significantly enhanced ferromagnetism. It was also found that the crystallization and ferromagnetic properties of the BNF thin films were enhanced when x is increased from 0.075 to 0.125. The observed macroscopic magnetization was concluded to be the result of suppressed space-modulated spin structure of BNF thin films.