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Current induced spin–orbit torque (SOT) switching of magnetization is a promising technology for nonvolatile spintronic memory and logic applications. In this work, we systematically investigated the effect of Ta thickness on the magnetic properties, field-free switching and SOT efficiency in a ferromagnetically coupled Co/Ta/CoFeB trilayer with perpendicular magnetic anisotropy. We found that both the anisotropy field and coercivity increase with increasing Ta thickness from 0.15 nm to 0.4 nm. With further increase of Ta thickness to 0.5 nm, two-step switching is observed, indicating that the two magnetic layers are magnetically decoupled. Measurements of pulse-current induced magnetization switching and harmonic Hall voltages show that the critical switching current density increases while the field-free switching ratio and SOT efficiency decrease with increasing Ta thickness. Both the enhanced spin memory loss and reduced interlayer exchange coupling might be responsible for the β DL decrease as the Ta spacer thickness increases. The studied structure with the incorporation of a CoFeB layer is able to realize field-free switching in the strong ferromagnetic coupling region, which may contribute to the further development of magnetic tunnel junctions for better memory applications.

The current-induced magnetization switching and damping-like field in Pt/(Co/Pt)/PtMn trilayer films prepared with and without an

As one of the most urgent public health events, coronavirus disease 2019 (COVID-19) has attracted worldwide attention. This case highlighted the importance of close coordination between Chinese medicine and western medicine in the diagnosis and treatment, as well as the need for rapid dissemination of clinical information related to patient care with this emerging infection. We reported a COVID-19 case confirmed in China and described the identification, diagnosis, clinical course, and management of the case. The patient had initial mild symptoms at presentation; it progressed to severe pneumonia on the 10th day of onset. This cured case supplied a time series analysis of tongue characteristics found in severe COVID-19. Chinese medicine formulae were tweaked by tongue characteristics, which include tongue color, fur thickness, and fur color. Tongue images were obtained every two days, and the changes were firmly related to the progression of COVID-19. These tongue characteristics could be used as effective, non-intrusive indices for the distinct stages of COVID-19 stages. Our study was the first time tongue diagnosis was applied in time series analysis of the progression of COVID-19 disease. We found that tongue color, fur thickness, and fur color were closely related to the progression of COVID-19 by analyzing various tongue images obtained regularly. Based on this success, we will further apply tongue diagnosis to tongue characteristics of COVID-19 patients to help limit the risk of COVID-19.