Untersuchung der anisotropen und dynamischen magnetischen Eigenschaften von Heusler Verbindungen und Doppelperowskiten durch Messung des Drehmoment in der Elektronenspinresonanz
Zusammenfassung der Projektergebnisse
My project was dedicated to an investigation of anisotropic and dynamic magnetic properties of Heusler compounds and double perovskites by means of torque detected electron spin resonance. During its time I have measured at a low temperature frequency and angular dependences of FMR signals of a set of Co2FeAl0.5Si0.5 films with different thickness, of a set of Co2FeSi films prepared at different conditions, and of Sr2FeMoO6 thin film. To perform these measurements, firstly, I modified the measurement setup in order to increase the signal to noise ratio. After that my study showed that all the investigated samples exhibit a relatively strong FMR response detected through the cantilever deflection. This FMR response shares some qualitative similarities, namely, at higher frequencies (above 80 GHz) the FMR signal splits into two lines, the linewidths of both lines are rather broad, and the linear fit of the frequency dependences yields a rather high g-factor values. All these findings are nontrivial and need to be further investigated in details, namely it is important to understand the origin of the second line, which exhibits an inverse angular dependence. It is also important to find the reason for such a large linewidth and the high slope of the frequency vs resonance field dependence. To answer these questions I am working on an appropriate model to fit the data. Notably, that even a preliminary quantitative analysis of the data yields an important information on anisotropic and dynamic magnetic properties of studied materials, as has been shown in the case of the set of Co2FeAl0.5Si0.5 films with different thicknesses. The FMR investigation of Co2FeAl0.5Si0.5 films with thicknesses of 200 nm, 120 nm, 84 nm, 45 nm, and 20 nm I have presented at the international electron spin resonance conference APES- IES-SEST 2014 in Nara, Japan. For the work I have shown there, I received the Best Poster Award.
