Low-dimensional quantum materials that remain strongly ferromagnetic down to monolayer thickness are highly desired for spintronic applications. Although oxide materials are important candidates for next generation of spintronics, ferromagnetism decays severely when the thickness is scaled to the nanometer regime, leading to deterioration of device performance. Here we report a methodology for maintaining strong ferromagnetism in insulating LaCoO3 (LCO) layers down to the thickness of a single unit cell. We find that the magnetic and electronic states of LCO are linked intimately to the structural parameters of adjacent "breathing lattice" SrCuO2 (SCO). As the dimensionality of SCO is reduced, the lattice constant elongates over 10% along the growth direction, leading to a significant distortion of the CoO6 octahedra, and promoting a higher spin state and long-range spin ordering. For atomically thin LCO layers, we observe surprisingly large magnetic moment (0.5 μB/Co) and Curie temperature (75 K), values larger than previously reported for any monolayer oxide. Our results demonstrate a strategy for creating ultrathin ferromagnetic oxides by exploiting atomic heterointerface engineering, confinement-driven structural transformation, and spin-lattice entanglement in strongly correlated materials.
Background: Flipped classroom has received much attention during the last few years in China, but inconsistent conclusions are made about the effectiveness this approach in health professions education. This review examined the findings of controlled studies published in Chinese in order to summarize the effects of the flipped classroom methodology. These studies focused specifically on undergraduate level of health professions students. Methods: A literature search was conducted using China National Knowledge Infrastructure (CNKI) and Wanfang Data Knowledge Service Platform in June 2019. No date restrictions were used. Peer-reviewed papers were reviewed and experimental studies were included if the study compared student outcomes using flipped classroom method versus traditional lectures. The revised version of the Kirkpatrick’s model was applied to evaluate the effectiveness of the flipped classroom approach. Results: In total, 934 articles were obtained. Among them, 235 articles were full text reviewed and 59 met the inclusion criteria. Most of the student agreed that flipped classroom strategy was very helpful improving their self-learning ability, problem solving ability, teamwork, and communication skills, but reported increased workload and less-efficiency compared with traditional lectures. However, the majority of studies (n = 52) showed positive findings of the flipped classroom on changes in knowledge and skills, and 3 in negative. Among these 59 studies, there was little evidence of changes in behavior, organizational practice and patient outcome. Conclusions: Better design with reduced content should be considered for instructors to promote learning effectiveness. Long-term effects of flipped classroom should be considered in future studies.
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