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Interfacial perpendicular magnetic anisotropy (PMA) in CoFeB/MgO structures was investigated and found to be critically relied on underlayer material and annealing temperature. With Ta or Hf underlayer, clear PMA is observed in as-deposited samples while no PMA was shown in those with Pt or Pd. This may be attributed to smaller saturation magnetization of the films with Ta or Hf underlayer, which makes the PMA of CoFeB/MgO interface dominates over demagnetization field. On the contrary, samples with Pt or Pd demonstrate PMA only after annealing, which might be due to the CoPt (or CoPd) alloy formation that enhances PMA.

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Reverse electrodialysis (RED) is an emerging technology that can generate electricity from the mixing of two water streams (i.e., the concentrated and the diluted streams) with salinity gradient. In RED, the higher salinity gradient between water streams yields the higher power production. Therefore, water sources containing a high concentration of salts such as reverse osmosis brine, hypersaline lakes, and produced water from hydraulic fracturing could be considered as feed streams for enhancing energy production in RED. However, these water sources contain not only NaCl but also various multivalent ions, which are likely to increase electrical resistance of ion exchange membranes (IEMs) and potentially decrease power generation. In this study, we investigated the effects of divalent cations in the concentrated stream, including magnesium, calcium, and barium ions on electrical resistance of IEMs in static mode. The electrical resistance of IEMs in static mode was found to be correlated to power production in a bench-scale RED process during continuous operation. As a result, it was found that divalent cation with the smaller hydrated radius showed the higher electrical resistance in the static mode and the increased electrical resistance of cation exchange membrane (CEM) resulted in power reduction during the continuous operation of the bench-scale RED process.

Magnetic and spintronic media have offered fundamental scientific subjects and technological applications. Magneto-optic Kerr effect (MOKE) microscopy provides the most accessible platform to study the dynamics of spins, magnetic quasi-particles, and domain walls. However, in the research of nanoscale spin textures and state-of-the-art spintronic devices, optical techniques are generally restricted by the extremely weak magneto-optical activity and diffraction limit. Highly sophisticated, expensive electron microscopy and scanning probe methods thus have come to the forefront. Here, we show that extreme anti-reflection (EAR) dramatically improves the performance and functionality of MOKE microscopy. For 1-nm-thin Co film, we demonstrate a Kerr amplitude as large as 20° and magnetic domain imaging visibility of 0.47. Especially, EAR-enhanced MOKE microscopy enables real-time detection and statistical analysis of sub-wavelength magnetic domain reversals. Furthermore, we exploit enhanced magneto-optic birefringence and demonstrate analyser-free MOKE microscopy. The EAR technique is promising for optical investigations and applications of nanomagnetic systems.