Surface Roughness Effects on Magnetization Reversal of Magnetic Ring Elements
The effect of surface roughness on magnetoresistance of permalloy ring structure is investigated. Microstructured permalloy rings with surface roughness varying from 4.2 to 21 nm were fabricated using electron beam lithography and a chemical etching process. It is found experimentally that the first and second nucleation fields decrease obviously with the surface roughness increasing, and the field range for the flux-closure state is not associated with surface roughness. The results indicate that surface roughness in permalloy ring structure is an important factor that influences the magnetic behaviors of the ring. This result can provide important information for future designs of ring-shaped magnetic devices.
Surface plasmon induced enhancement with magneto-optical layer
In this study, we examined surface plasmon resonance (SPR) induced magneto-optical (MO) Kerr signals, and obtained a complete SPR curve in multilayered metallic structures comprising 6-nm-thick Au, t-nm-thick Permalloy (Py), and 26-nm-thick Au layers (with various thicknesses of Py). As the thickness of the Py layer increased, the SPR weakened. The MO signals were exhibited to various magnitudes of amplification while measuring the hysteresis loop at different segments of the SPR curve, which were the product of the MO Kerr effect. The MO signals between the reflectance maximum and reflectance minimum of the SPR were enhanced significantly in the samples with a 2 to 20-nm-thick Py layer. After measuring and analyzing the MO signals from multiple specimens with various thicknesses of Py, the optimal thickness of the Py layer was 10 nm, at which the strongest signal amplification was obtained.
Growth from Solutions
Growth from solutions is the crystallization of a compound whose chemical composition differs markedly from that of the initial liquid phase. Commonly used solvents are water, multicomponent aqueous or nonaqueous solutions, and melts of some chemical compounds. Differentiations are made based on growth temperatures and on the chemical nature of the solvent. In growth from low-temperature aqueous solutions, the temperatures generally do not exceed 80–90°C; in growth from superheated aqueous solutions (hydrothermal method), they reach 800°C, and in growth from salt melts (molten-salt, flux, or fluxed melt growth), they usually do not exceed 1200–1300°C, but sometimes reach 1500°C.