Papers by Author: Takayoshi Sasaki

Abstract: Two-dimensional (2D) Ti1-xCoxO2 nanosheet, a recently discovered ferromagnic nanomaterial, has been investigated by magnetic and magneto-optical measurements. The multilayer films of Ti0.8Co0.2O2 nanosheets exhibit room-temperature ferromagnetism with magnetic moment of 1.4 μ B/Co. We also observe robust magnetic circular dichroism near the absorption edge at 4 eV, indicating a strong spin polarization in this 2D system. The first-principles study of Ti1-xCoxO2 nanosheet characterizes the ferromagnetic state with a spin-orbit-induced anisotropy.

Abstract: We have demonstrated a fabrication procedure for spin-electronic devices by using two-dimentional titania nanosheets. Magneto-optical Kerr measurements demonstrate that Co-substituted titania nanosheets (Ti0.8Co0.2O2) act as nanoscale ferromagnetic layers at room temperature, and their multilayer-assemblies exhibit robust magnetic circular dichroism (104–105 deg/cm) near the absorption edge at 260 nm, an operating wavelength being the shortest attained so far. The availability of ferromagnetic nanostructures and their molecule-level assembly allow the rational design and construction of high-efficiency magneto-optical devices by forming superlattices.