Charge Transfer Induced In-Plane Coercivity Change in Hetero-Nanostructure :
C60/Ni/Cu(001)
S.-S. Wong (翁聖勛)1, N.-Y. Jih (紀乃友)1,2, C.-H. Chuang (莊程豪)1,2, C.-W. Peng (彭治維)1,
Y.-M. Chang (張銀銘)1, L.-Y. Chang (張羅嶽)2, H.-W. Shiu (許紘瑋)2, Y.-L. Chan (陳悅來)2,
W.-W. Pai (白偉武）4, Y.-J. Hsu (許瑤真)2, D.-H. Wei (魏德新)2, C.-H. Chen (陳家浩)2,
and M.-T. Lin (林敏聰)1,3
1
Department of Physics, National Taiwan University, Taipei, Taiwan
National Synchrotron Radiation Research Center, Hsinchu, Taiwan
3
Institute of Atomic and Molecular Science, Academia Sinica, Taipei, Taiwan
4
Center of Condense Matter Science, National Taiwan University, Taipei, Taiwan
2
Charge transfer between adsorbate and substrate is not uncommon in surface science. When
the substrate is a magnetic ultrathin film, however, the deposition introduced charge transfer may
trigger unexpected behavior/property in the thin films. In this presentation, we report the variation
of magnetic properties in Ni layer upon C60 deposition. The possible origin responsible for the
observed phenomena is discussed in terms of electronic structures probed by the X-ray
photoemission spectroscopy (XPS). The experimental system examined here is C60/Ni(12
ML)/Cu(001). Based on the magneto-optical Kerr effect (MOKE) measurements, we found the
deposition of 1 ML C60 can significantly reduce the in-plane coercivity in Ni layer, yet the
perpendicular coercivity shows little variation at the same time. In the XPS measurements
performed on C60(0.9 ML)/Ni(12 ML)/Cu(001), we observed a low binding energy shoulder (284
eV) appears beside the C 1s peak (284.4 eV) along with a 0.2 eV chemical shift of Ni 3P3/2 from
65.7 eV to 65.9 eV. The reduced in-plane coercivity would be induced by the change in magnetic
surface aniosotrpy, which could be correlated to charge transfer between Ni and C60 at
hetero-interface.