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As electrical control of magnetization dynamics opens the door to realize spintronic devices, understanding the microscopic mechanisms of spin current transport and its effect through the antiferromagnetic and interface is crucial. We studied magnetization dynamics modulated by the spin current originated from the spin-orbit-torque using the rectifying planar Hall effect (PHE). In Ni81Fe19/NiO/Ni81Fe19 heterostructure wire deposited on Pt/Ta cross-tie electrode, we measured the rectifying PHE as a function of external magnetic field angle and dc electric current. By measuring the electrical responses of the heterostructure system, we found that the magnetization dynamics can be modulated by the dc electric current flowing through the Pt/Ta electrode.

Anisotropic pyrochemical micro-etching induced by synchrotron x-ray irradiation is developed as a microfabrication process for fluorinated ethylene propylene (FEP). X-ray irradiation is performed at room temperature, and the irradiation area is etched by heating in an oven. By measuring the irradiation area using Raman spectroscopy, the peak of the Raman spectrum is shown to decrease with an increasing irradiation dose. It is also observed that the etching can be performed at a heating temperature of around 200 °C while maintaining the chemical composition of the surface. The etching mechanism is speculated to be as follows: x-ray irradiation causes chain scission, which decreases the number-average degree of polymerization. The melting temperature of irradiated FEP decreases as the polymer chain length is decreased so that the irradiated area can be evaporated at low temperatures of post-heating. In this way, we demonstrate that anisotropic pyrochemical micro-etching of FEP proceeds only in the depth direction where x rays are absorbed. It is possible to avoid deterioration of the shape accuracy arising from thermal expansion during the transfer process of the mask pattern by separating pre-irradiation from post-heating. Through this method, it becomes possible to realize a high precision microstructure of FEP in a large area.

The electrical ferromagnetic resonance of micro-scale Ni wires with magnetic anisotropy induced by the heterojunction between the Ni layer and ferroelectric single crystalline LiNbO3 substrate was demonstrated by using rectifying effect. The two resonance modes were observed in the Ni wire aligned parallel to the applied magnetic field in plane. The lower resonance frequency mode is considered to correspond to the normal resonance mode with domain resonance, while the higher resonance mode is attributed to the mode which is contributed by the heterojunction between the Ni layer and LiNbO3 substrate. Our results manifest that the rectifying electrical detections are very useful for understating and evaluating the magnetic properties induced by the heterojunction.