To achieve the three dimensional additive manufacturing process, we investigated X-ray radiolysis-induced photochemical reaction of Cu(CH 3 COO) 2 solution. Here, we demonstrated synthesis and immobilization of copper and copper oxide particles onto an aluminium substrate directly from the liquid solution. The particles are formed in the X-ray radiolysis of flowing aqueous solutions of Cu(CH 3 COO) 2 which also contain methanol as ⋅ OH scavenger. We found that the sizes and compositions of the particles depend on the flow rate of solution. The results indicate that there are several routes and reaction processes for these particles formation and their aggregation. Our study will shed light on understanding and providing a novel photochemical reaction route induced under the X-ray irradiation. The development of X-ray radiolysis-induced photochemical reaction process enables us to achieve the rapid and easy formation of higher-order nano/ micro-scale structures consisting of composite materials.

We investigated the magnetoresistive property of a micrometer-scale Ni wire with a uniaxial magnetic anisotropy induced by the formation of a heterojunction between a Ni layer and a single-crystal lithium niobate (LiNbO 3) substrate. We revealed that the domain structure can be controlled by adjusting the wire alignment and that its magnetoresistance (MR) is dependent on the magnetic domain structure as well as the reversal process. The introduction of a heterojunction is a crucial method of controlling the magnetic domain structure owing to the additional generation of the magnetic anisotropy. This control of the magnetic domain structure is very useful for investigating the fundamental physical mechanism and producing artificial multiferroic functional materials and devices. The relatively large MR response observed in transport measurements alludes to the possibility that the spin-dependent scattering mechanism occurs in the domain and domain wall.

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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.

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Schematic drawing of electrochemical reactions of the Pt-coated SiC electrode, which separates the vacuum and the solution containing Ni2+ and ethylene glycol, in our spectro-electrochemical setup for the FY-XAS.

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The rectifying electric ferromagnetic resonance spectroscopy was performed to examine the magnetization dynamics in the stripe magnetic domain structure induced by the competition between shape and heterojunction-induced magnetic anisotropy. The observed angle dependence is in good agreement with the analytical calculations based on the macro-spin model when the applied magnetic field is larger than the effective magnetic anisotropy field. When the external magnetic field is smaller than the threshold field at which destroys the stripe domain structure is destroyed, a large rectifying amplitude is generated in a Ni wire aligned perpendicular to the x-axis of the substrate. The relatively large response is attributed to that the coupled oscillations of the stripe domains. In addition, the Gilbert damping factor is found to be enhanced in the system because of stripe domain structure formation and strain-induced modulation.