The aim of this work is to fabricate an all-oxide spin valve using multiferroic BiFeO 3 as the antiferromagnetic pinning layer, in the hope that we may be able to switch magnetoresistance electrically. The proposed architecture is Zn 0.7Ni 0.3Fe 2O 4/ Sr 1-xLa xTiO 3/ Zn 0.7Ni 0.3Fe 2O 4/ BiFeO 3/ LaNiO 3/SrTiO 3. We have demonstrated that such a multilayer structure can be grown epitaxially by the RF magnetron sputtering. X-ray diffraction showed that the films were indeed biaxially aligned with reasonable in-plane and out-of-plane textures, under the growth conditions optimised for achieving good ferroelectric and magnetic properties. X-ray photoelectron spectroscopy depth profiling showed that there was significant Bi diffusion across the interface if the BiFeO 3 film was not stabilised in high oxygen ambience after deposition. High-resolution transmission electron microscopy showed a tidy and sharp Zn 0.7Ni 0.3Fe 2O 4/ BiFeO 3 boundary for the Zn 0.7Ni 0.3Fe 2O 4 films grown at 550 °C, while for the films grown at higher temperature an irregular interface was observed. Under the optimum growth condition, a clear exchange bias was achieved at the Zn 0.7Ni 0.3Fe 2O 4/ BiFeO 3 interface.
All Science Journal Classification (ASJC) codes
- 化學 (全部)