Fachbereich 11 - Physik
Institut für Materialphysik
Nanoanalysis of Interreactions

Thermal stability of GMR sensor devices

The thermal stability of sensor devices based on the giant magneto-resistance effect is important for any application at elevated temperatures. We studied atomic transport and segregation by means of atomprobe tomography. In spin-valve structures of the quaternary units Cu/FeNi/Cu/Py an important texture change by recrystallization takes place during heat treatments at 350°C. Furthermore, Ni segregation at the grain boundaries in Cu and Fe segregation at the Co interfaces is detected. Ni segregation provides a coupling mechanism between different ferromagnetic layers which will decrease the effect amplitude, while the Fe segregation may be interpreted as an natural interface dusting, that potentially improves the sensor properties.

Drittmittelgeber:

Deutsche Forschungsgemeinschaft (Einzelprojekt)

Beteiligte Wissenschaftler:

J. Schleiwies, C. Ene (Univ. Göttingen), S. Heitmann, A. Hütten (Univ. Bielefeld), G. Schmitz (Projektleiter)

Veröffentlichungen:

J. Schleiwies, G. Schmitz, S. Heitmann, A. Hütten, Nanoanalysis of Co/Cu/NiFe thin films by tomographic atom probe, Appl. Phys. Lett. 78, 3439, 2001

J. Schleiwies Dissertation, Göttingen 2001