Direct observation of a magnetic domain change in Ni wire and film on a LiNbO₃ substrate using X-ray magnetic circular dichroic photoemission electron microscopy

Abstract

The magnetic domain structure modulation in Ni wires deposited on a LiNbO3 substrate is observed during the application of a DC current or heating. A striped domain structure is formed in the Ni wires that is aligned perpendicular to the X-axis of the LiNbO3 substrate owing to the competition between magnetic shape anisotropy and uniaxial magnetic anisotropy from the heterojunction. We observe that the striped domain structure disappears as the DC current is increased. In the same manner, it is also confirmed that the striped magnetic domain structure disappears as the substrate is heated. These results are considered to arise from the decrease in uniaxial magnetic anisotropy and magnetization owing to an oxidation reaction at the interface. Heterojunctions are identified to play an important role in controlling and modulating the magnetic properties of this system.

In situ fluorescence yield soft X-ray absorption spectroscopy of electrochemical nickel deposition processes with and without ethylene glycol

“…For further assignments of these transitions to the exact 3d orbital, careful experiments in the magnetic field and theoretical calculations are needed. The peaks around 851 and 869 eV, which are found at lower energies in each transition, can be associated with metallic Ni 35,49 whereas the peaks around 853 and 870 eV, which are found at higher energies in each transition, can be assigned to NiO. 16,50,51 Thus, in situ FY-XAS using our spectro-electrochemical flow cell allows us to detect the deposition of Ni and NiO on the Pt electrode.…”