Experimental Physics III

Topological Magnetic Devices


Spintronic is a relatively new topic which combines magnetoelectronics and semiconductor technology (Also see 'A little bit on spintronics'). It is based on transport and manipulation of electrons in a semiconductor which have a well defined spin orientation. Applications range from new devices like transistors or memory cells to quantum computing in semiconductor nanostructures. In comparisin to other fields of research, spintronics include the unique opportunity to do basic research in a field existing only since a few years while working very close to applications because any new idea can be of value for a new patent or open up new areas of experimental research. This is why research in our group extends from basic studies of electronic effects to the development of novel magnetoelectronic devices. Most of our experiments are carried out at low temperatures and high magnetic fields. As a spintronic device always has to be smaller than the mean length on which a spin information is lost, all our research is carried out on nanostructures.


For our experiments in spintronics we need a large variety of nanostructures based on semiconductors and/or metals. These nanostructures are fabricated in our group using electron beam lithography and different patterning techniques. Lateral dimensions which were achieved up to now by our group are among the smallest obtained worldwide (5 nm in metals and 12 nm in semiconductors). However small is not the only thing. Complex devices like vertical semiconductor quantum dots require high sophisticated contacting technologies. E. g. we have fabricated freestanding metal airbridges onlya few 100 nanometers wide. Besides applications in spintronics also other lithography techniques are developed. Among these are nanoimprint lithography and microcontact printing. Some nice pictures are available here.