December 14, 2010 16:15 - 17:15
Empa, Dübendorf, Theodor-Erismann-Auditorium, VE102
The rational design of new functional materials is the dream of every materials scientist. Precondition for the development of a design scheme is a structure type, in which many interesting properties can be found. An important class of materials with potential for applications in electronic devices and green energy are those of the Heusler and half-Heusler families. The latter are ternary semiconductors XYZ which exhibit the C1b structure: more than 250 compounds, nearly all semiconductors, are known to take up this structural type. Of particular interest the band gap can be tuned from almost 4 eV to zero. Thus, these materials have attracted attention as potential candidates for both solar cell (wide band gap), thermoelectric applications (low band gap) and topological insulators. Different properties such as spin quantum hall effect and superconductivity can be combined in this material class.
The Heusler compounds X2YZ have been explored recently in the context of spintronics. Some Heusler compounds, especially the family Co2YZ have been demonstrated to be half-metallic ferromagnets in which the conduction electrons are almost fully spin polarized. Moreover, these materials exhibit very high Curie temperatures up to 1200 K and low damping constants lower than permalloy. Mn3Ga is an example for a tetragonal Heusler compound with perpendicular anisotropy, a high Curie temperature and a low magnetic moment. This class of materials has a high potential for spin torque application in STTRAM and spin torque ocillators. Several new tetragonal Heuslers are designed for spin torque applications.
The language of the presentation is English.
Free entrance, guests are welcome
Dr. Anne Satir
Tel: 044 823 4562