Wen-Bin Jian | Searcharxiv

arXiv2020

Memory device employing hysteretic properties of a tungsten filament in superfluid helium-4

A tungsten filament immersed in superfluid helium has strong hysteretic $I$-$V$ characteristics. By increasing the applied voltage, a remarkable current drop occurs at a transition voltage, at which the filament enters a non-ohmic hot state and becomes covered with a helium gas sheath. The return to an ohmic state occurs at a lower voltage because of the poor heat conduction of the gas sheath. Hence, the $I$-$V$ characteristic is strongly hysteretic. The stable hysteresis window was employed to fabricate a novel memory device, which demonstrated fast switching and stable reading.

physics.app-ph↗

arXiv2015

Exposure of the Hidden Anti-Ferromagnetism in Paramagnetic CdSe:Mn Nanocrystals

We present theoretical and experimental investigations of the magnetism of paramagnetic semiconductor CdSe:Mn nanocrystals and propose an efficient approach to the exposure and analysis of the underlying anti-ferromagnetic interactions between magnetic ions therein. A key advance made here is the build-up of an analysis method with the exploitation of group theory technique that allows us to distinguish the anti-ferromagnetic interactions between aggregative Mn2+ ions from the overall pronounced paramagnetism of magnetic ion doped semiconductor nanocrystals. By using the method, we clearly reveal and identify the signatures of anti-ferromagnetism from the measured temperature dependent magnetisms, and furthermore determine the average number of Mn2+ ions and the fraction of aggregative ones in the measured CdSe:Mn nanocrystals.

cond-mat.mes-hall↗