We obtained epitaxial single-crystal Fe3O4(001)/MgO(001) thin films by magnetron sputtering. The high quality of the grown Fe3O4 films was confirmed by reflection high-energy electron diffraction and x-ray photoelectron spectroscopy. Atomic magnetic properties of Fe3O4(001)/MgO(001) were investigated using vibrating sample magnetometry and x-ray magnetic circular dichroism. The values of saturation magnetization and magnetic moment are 407 ± 5 emu/cm3 (3.26 ± 0.04 μ B / (f. u.)) and 3.31 ± 0.15 μ B / (f. u.), respectively, in the Fe3O4 film as thin as 5 nm, which are close to the bulk values. The spin polarization was directly measured using spin-resolved photoemission spectroscopy. The measured spin polarization has a maximum value of -42% ± 3%, which is comparable to the theoretical value for the (2 × 2)R45° reconstructed Fe3O4(001) surface. Furthermore, the film thickness-dependent measurements indicate that the anti-phase boundaries significantly decrease the spin polarization rather than the lattice mismatch. Our results demonstrate that epitaxial Fe3O4(001)/MgO thin films grown by magnetron sputtering have desired magnetic properties, facilitating the potential application of Fe3O4-based spintronic devices.
|Number of pages||7|
|Journal||Applied Physics Letters|
|Publication status||Published - 3 May 2022|
Bibliographical noteFunding Information:
This work was supported by the National Key Research and Development Program of China (Grant No. 2021YFB3601600), the National Natural Science Foundation of China (Grant Nos. 12104216 and 61427812), and the Natural Science Foundation of Jiangsu Province of China (Nos. BK20200307, BK20192006, and BK20180056). The authors would like to thank the staff at BL07U beamline of the Shanghai Synchrotron Radiation Facility (SSRF) for assistance with XMCD/XAS data collection.
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