Publications by authors named "Kanta Asakawa"
Light-induced desorption of Rb atoms from a ferrimagnetic Fe[Formula: see text]O[Formula: see text](001) surface was studied using a spin-selective optical method, which provides information on the spin polarization, velocity distribution, and amount of the desorbed atoms. The results showed that the intensity of the desorption of Rb from Fe[Formula: see text]O[Formula: see text](001) induced by ultraviolet (UV) light irradiation was smaller than the detection limit at coverages lower than the threshold coverage at which the desorption rate began to increase. Moreover, the average magnetic quantum number of the desorbed atoms was smaller than that of electrons at the Fermi level of the Fe[Formula: see text]O[Formula: see text](001) surface.
View Article and Find Full Text PDFWe measured the magnetic hysteresis and coercivity of individual Co and CoFe bilayer nano-sized island structures formed on Cu (111) substrate using spin-polarized scanning tunneling microscopy. From the hysteresis taken on various sizes of islands, we found that the alloyed islands are ferromagnetic with out-of-plane magnetic anisotropy, same as the pure islands. Coercivity of the alloy islands, which is dependent on their size, was significantly reduced to ≈40% of that of the pure islands.
View Article and Find Full Text PDFWe characterized the performance of electrochemically etched bulk Fe and Ni tips as a probe of spin-polarized scanning tunneling microscopy (SP-STM). Through the observation of the striped contrast on the conical spin-spiral structure formed in Mn double layers on a W(110) substrate, the capability of both the tips to detect the magnetic signal was clarified. We also confirmed that the magnetized direction of the Fe and Ni tips can be flipped between the two out-of-plane directions by external magnetic fields.
View Article and Find Full Text PDF