Recent work on magnetic quantum point contacts (QPCs) was discussed. Complete magnetoresistance loops across Co QPCs as small as a single atom was measured. The remarkable feature of these QPCs is the rapid oscillator...Recent work on magnetic quantum point contacts (QPCs) was discussed. Complete magnetoresistance loops across Co QPCs as small as a single atom was measured. The remarkable feature of these QPCs is the rapid oscillatory decay in magnetoresistance with the increase of contact size. In addition, stepwise or quantum magnetoresistance loops are observed, resulting from varying transmission probability of the available discrete conductance channels because the sample is cycled between the ferromagnetic (F) and antiferromagnetic (AF) aligned states. Quantized conductance combined with spin dependent transmission of electron waves gives rise to a multi-channel system with a quantum domain wall acting as a valve, i.e., a quantum spin-valve. Behavior of a few-atom QPC is built on the behavior of a single-atom QPC and hence the summarization of results as ‘single-atom spintronics’. An evolutionary trace of spin-dependent electron transmission from a single atom to bulk is provided, the requisite hallmarks of artefact-free magnetoresistance is established across a QPC – stepwise or quantum magnetoresistance loops and size dependent oscillatory magnetoresistance.展开更多
We report that La60Fe30Al10 metallic glass has clear,reproducible,periodic variation in its differential resistance as a function of a perpendicular magnetic field below its superconducting transition temperature. The...We report that La60Fe30Al10 metallic glass has clear,reproducible,periodic variation in its differential resistance as a function of a perpendicular magnetic field below its superconducting transition temperature. The oscillation period corresponds to a superconducting flux quantum. The observed phenomena originate from the Little-Parks-like resistance oscillations in the cylindrical La nanorod with a high aspect ratio and uniform orientation precipitated on the ribbon surface. The highly-oriented La nanocrystals prepared on a flexible glass substrate offer an opportunity for integrating numerous superconducting circuits into a single chip.展开更多
文摘Recent work on magnetic quantum point contacts (QPCs) was discussed. Complete magnetoresistance loops across Co QPCs as small as a single atom was measured. The remarkable feature of these QPCs is the rapid oscillatory decay in magnetoresistance with the increase of contact size. In addition, stepwise or quantum magnetoresistance loops are observed, resulting from varying transmission probability of the available discrete conductance channels because the sample is cycled between the ferromagnetic (F) and antiferromagnetic (AF) aligned states. Quantized conductance combined with spin dependent transmission of electron waves gives rise to a multi-channel system with a quantum domain wall acting as a valve, i.e., a quantum spin-valve. Behavior of a few-atom QPC is built on the behavior of a single-atom QPC and hence the summarization of results as ‘single-atom spintronics’. An evolutionary trace of spin-dependent electron transmission from a single atom to bulk is provided, the requisite hallmarks of artefact-free magnetoresistance is established across a QPC – stepwise or quantum magnetoresistance loops and size dependent oscillatory magnetoresistance.
基金supported by the National Natural Science Foundation of China (51101056, 50731008 and 50921091)the National Basic Research Program of China (2007CB613904)+1 种基金the Fundamental Research Funds for the Central Universities (09Q44)the State Key Lab of Advanced Metals and Materials (2010Z-02)
文摘We report that La60Fe30Al10 metallic glass has clear,reproducible,periodic variation in its differential resistance as a function of a perpendicular magnetic field below its superconducting transition temperature. The oscillation period corresponds to a superconducting flux quantum. The observed phenomena originate from the Little-Parks-like resistance oscillations in the cylindrical La nanorod with a high aspect ratio and uniform orientation precipitated on the ribbon surface. The highly-oriented La nanocrystals prepared on a flexible glass substrate offer an opportunity for integrating numerous superconducting circuits into a single chip.
