RESUMO
The current-induced magnetization switching and damping-like field in Pt/(Co/Pt)/PtMn trilayer films prepared with and without an in situ in-plane field of 600 Oe have been studied systematically. In the presence of the in situ field, a small in-plane bias field (HEB) is observed for films with PtMn thickness ≥5 nm, while there is no observable HEB for PtMn thickness ≤3 nm. Nevertheless, a field-free switching of perpendicular magnetization of Co/Pt is observed for all the films with the PtMn thickness of 1-7 nm. On the other hand, without the presence of the in situ field, HEB and field-free switching are not seen. Furthermore, the damping-like fields (HDL) are much enhanced in the presence of the in situ field, and the increasement can be up to 47%. We further revealed that the spin current is mainly from the Pt layer, while the noncollinear spin configuration at the interface caused by the in situ in-plane field may play a role in the HDL enhancement. Micromagnetic simulations indicate that the canting of antiferromagnet PtMn spins plays an important role in the field-free switching. Our findings clarify the source of spin current in the trilayer films and provide an easier approach to field-free switching and HDL enhancement for future low-power spintronic devices.
RESUMO
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.