Currently, people investigating the magnetic properties of ferromagnets at low temperatures have found that there exists a class of magnetic alloys such as SmCo<sub>3.5</sub>Cu<sub>1.5</sub>, S...Currently, people investigating the magnetic properties of ferromagnets at low temperatures have found that there exists a class of magnetic alloys such as SmCo<sub>3.5</sub>Cu<sub>1.5</sub>, Sm（CoCuFeTi）<sub>6.8</sub>, Tb(Fe<sub>0.7</sub>Al<sub>0.3</sub>)<sub>2</sub>, Dy(Fe<sub>0.9</sub>Ga<sub>0.1</sub>)<sub>2</sub>, of which the curves of coercive force H<sub>c</sub> versus temperature T are logarithmic shapes at high temperatures and ap-展开更多
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
基金Project supported by the National Natural Science Foundation of China
文摘Currently, people investigating the magnetic properties of ferromagnets at low temperatures have found that there exists a class of magnetic alloys such as SmCo<sub>3.5</sub>Cu<sub>1.5</sub>, Sm（CoCuFeTi）<sub>6.8</sub>, Tb(Fe<sub>0.7</sub>Al<sub>0.3</sub>)<sub>2</sub>, Dy(Fe<sub>0.9</sub>Ga<sub>0.1</sub>)<sub>2</sub>, of which the curves of coercive force H<sub>c</sub> versus temperature T are logarithmic shapes at high temperatures and ap-
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.
