Hybrid improper ferroelectricity can effectively avoid the intrinsic chemical incompatibility of electronic mechanism for multiferroics. Perovskite superlattices, as theoretically proposed hybrid improper ferroelectrics with simple structure and high technological compatibility, are conducive to device integration and miniaturization, but the experimental realization remains elusive. Here, we report a strain-driven oxygen octahedral distortion strategy for hybrid improper ferroelectricity in LaNiMnO/LaCoMnO double-perovskite superlattices.
View Article and Find Full Text PDFSingle-phase multiferroics suffer from a fundamental contradiction between polarity and magnetism in d electronic configuration, motivating studies of unconventional ferroelectricity in magnetic oxides. However, low critical temperature and polarization still need to be overcome. Here, it is reported that the switchable polarization behavior at room temperature in [(La NiMnO )/(La CoMnO )] double-perovskite magnetic superlattice films is achieved by engineering a microstructure with gradient strains, and the ferromagnetic Curie temperature did not show a rapid decrease.
View Article and Find Full Text PDFBoth surface and interface scattering induced a sign reversal of the anomalous Hall effect (AHE) in a few heterostructures. The sign reversal existing in a single substance can clarify the role of the surface scattering in the AHE. Here, cluster-assembled Ni0.
View Article and Find Full Text PDFIn modern ion implanters, a plasma flood gun (PFG) is used to neutralize wafer charge during the doping process, preventing the breakdown of floating wafers caused by the space charge accumulation. Typically, there are two kinds of PFGs, namely, dc arc discharge with filament and RF discharge. As a PFG, the filament one has limited lifetime and cannot avoid metallic contamination because of the thermal emitting filament.
View Article and Find Full Text PDFA 2.45 GHz microwave-driven ion source for the generation of multicharged ions has been designed and built at Peking University recently. The magnetic field configuration of this ion source is a minimum-B type with a combination of a hexapole field and an axial mirror field.
View Article and Find Full Text PDFAt Peking University (PKU), experimental research as well as theoretical study on how to produce high intense H, H , or H dominated ion beams with a compact permanent magnet 2.45 GHz electron cyclotron resonance (PMECR) ion source have been continuously carried out in the past few decades. Based on the comprehension of hydrogen plasma processes inside a 2.
View Article and Find Full Text PDF