development of field ion-magnetic force microscope (FI-MFM) and its application to surface magnetism

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In this research project, we have developed an magnetic force microscope (MFM) combined with field ion microscope (FIM) for tip characterization and modification, using the system, we studied on surface magnetism. For a high performance of MFM, it is very important to characterize a tip, and thus we studied elemental distribution in the tip with an atomic scale spatial resolution using atom probe field ion microscope (APFIM).1. We developed a high performance STM combined with FIM for tip characterization. In order to check its performance, we observed STM images on metal surfaces and successfully achieved atomic resolution. We also studied adsorbate-induced reconstructed surface structures using the system. Those results are summerized in some review papers.2. study on surface magnetism on Mn/Cu(001) system :Surface magnetism is quite attractive subject in a physical point of view, but its relation with atomic structure have not been really understood well, In this study, we tried to investigate a relation of magnetic properties and atomic structure of surfaces using STM.Based on STM observation, we found that Mn atoms forms clusters in an initial stage of adsorption. Above a critical thickness, Mn adsorbate exchange its site with Cu atoms in the substrate, forming c(2x2) phase, until a half monolayer. Corrugation of the c(2x2) structure is not so much as reported with LEED.Our results are contradictory with the LEED results, which claims that Mn atoms protrude because of ferromagnetic interaction among the atoms.3. characterization of MFM tip by FILM and AP-FIM :It is inevitable to characterize precisely spin states and magnetic properties of tip apex. For the parposes, we performed atom probe analysis of magnetic material tip and studied a distribution of magnetic domains with nanometer scale spatial resolution.