离轴磁控溅射法生长1-3维PZT-NFO纳米复合薄膜

采用90°离轴磁控溅射法, 在MgAl₂O₄(001)单晶基片上自组装生长了Pb(Zr_0.52Ti_0.48)O₃-NiFe₂O₄ (PZT-NFO)复合磁电薄膜, 并研究了基片温度、氩氧比和溅射功率等因素对薄膜结构和性能的影响。结果表明, 适合生长PZT-NFO薄膜的条件为基片温度800℃, 氩氧比1:1, 溅射功率160 W。XRD测试显示, PZT-NFO薄膜为外延生长薄膜, 且PZT相与NFO相之间的垂直晶格失配非常小。AFM和SEM结构观察表明, 薄膜具有清晰的1-3维纳米复合结构, 铁磁相NFO纳米柱直径约为80~150 nm。降低氩氧比有助于NFO相的形成, 但溅射功率过大会造成1-3维结构向无规则0-3维结构转变。磁性能测量表明纳米复合薄膜的饱和磁化强度在120~160 kA/m之间, 低于块体的NFO相, 可能是由于两相的界面扩散所造成。

Preparation of 1-3 Dimensional PZT-NFO Nanocomposite Films by Off-axis Magnetron Sputtering

Self-assembled nanocomposite Pb(Zr_0.52Ti_0.48)O₃-NiFe₂O₄ films were prepared on the (001)-oriented MgAl₂O₄ substrates by a 90° off-axis magnetron sputtering method. The influences of substrate temperature, argon over oxygen ratio and sputtering power on the structure and properties of PZT-NFO nanocomposite films were studied. The optimal growth conditions are substrate temperature of 800 ℃, argon over oxygen ratio of 1:1 and sputtering power of 160 W. XRD studies reveal that the PZT-NFO film is epitaxial along both the in-plane and out-of-plane directions, and the vertical lattice mismatch between the PZT phase and the NFO phase is very small. AFM and SEM analysis show that the PZT-NFO films have clear 1-3 dimensional nanocomposite structure, and the diameter of NFO nanorods is 80-150 nm. Further decreasing argon over oxygen ratio is beneficial for the formation of NFO. However, increasing RF power causes a transition from an 1-3 dimensional nanocomposite to a 0-3 dimensional chaotic structure. Magnetic measurement shows that the saturation magnetization of NFO phase is 120-160 kA/m, lower than that of bulk NFO phase, possibly due to the interfacial diffusion between the NFO and the PZT phases.