Dresden 2009 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
DS: Fachverband Dünne Schichten
DS 20: Amorphous Thin Magnetic Films
DS 20.2: Topical Talk
Mittwoch, 25. März 2009, 16:15–16:45, GER 37
Thermodynamic stability and crystallization of amorphous thin magnetic films — •Ulrich Herr1, Andreas Grob1, Mohammad Mujeebuddin1, Xiaoxi He1, Senthilnathan Mohanan1, Rolf Diebolder2, and Raimund Hibst2 — 1Institut für Mikro- und Nanomaterialien, Universität Ulm, 89081 Ulm — 2Institut für Laseranwendungen in der Medizin und Meßtechnik, Universität Ulm, 89081 Ulm
The thermodynamic stability of thin films is strongly affected by the presence of surfaces and interfaces. We present results of the stabilization of FeZr films on different substrates. The initially amorphous films undergo a crystallization at a critical thickness, which depends on the thermodynamic driving forces. The crystallization occurs spontaneously at room temperature and can be monitored by changes of the magnetic and mechanical properties of the films. The results demonstrate the importance of the structural mismatch at the film-substrate interface for the stabilization effect. In the second part we report on crystallization of thin amorphous CoFeB films which are of interest for application in TMR devices with MgO tunnel barriers. The annealing treatment necessary for the crystallization may lead to unwanted interdiffusion and degradation of device properties. The intention of our study is to limit the interdiffusion by pulsed heating with nanosecond laser pulses. The progress of the crystallization is monitored by measurements of electrical resistivity, magnetic properties and structural investigation by X-ray diffraction. The effect of CoFeB film thickness and laser intensity on the crystallization process has been investigated.