Comparable to light propagating in phothonic crystals, magnetic spin waves can propagate in periodic magnetic structures classified as magnonic crystals. By tailoring the geometrical and material properties of the magnonic crystal as well as the excitation conditions, the sustained magnonic waves result in different characteristic dispersion diagrams suitable for different future ICT applications. Here, micromagnetic numerical simulations are important to interpret experimentally obtained dispersion relations as well as to predict the propagation properties under different conditions. To this end, we propose a new versatile simulation approach to determine the dispersion relations in magnonic structures in which we continuously excite the system at a fixed amplitude. Combining several simulations at different excitation frequencies, one can study the dispersion relation in the frequency range of interest without limits on the frequency resolution. This is very advantageous when one is aiming to study a specific spin wave mode or a bandgap in large detail. Moreover, by studying the magnetization response in the time domain, one can easily extract the temporal phase difference between the sustained magnonic waves on the one hand and the excitation at the other hand as well as the distinct mode profiles. We show that spin waves defining a magnonic band beat with a gradually varying phase differences with respect to the excitation. To show the applicability of the approach we apply it to three different classes of 2D magnonic crystals. Dispersion relations are determined or (i) a dotarray comprising closely interacting squares [1], (ii) an antidotarry defined by periodically placed circular holes in a Permalloy film [2] and (iii) a bicomponent crystal consisting of Permalloy and Cobalt squares arrangedin a chessboard pattern [3]. For the three classes, we validate the approach by comparing the simulation results with experimental data. [1] S. Tacchi et al., Phys. Rev. B 80, 024401 (2010). [2] R. Zivieri et al., Phys. Rev. B 85, 012403 (2012). [3] G. Gubbiotti et al. Appl. Phys. Lett. 100, 162407 (2012).
A novel micromagnetic simulation approach to determine dispersion relations in magnonic crystals.
MONTONCELLO, Federico;
2013
Abstract
Comparable to light propagating in phothonic crystals, magnetic spin waves can propagate in periodic magnetic structures classified as magnonic crystals. By tailoring the geometrical and material properties of the magnonic crystal as well as the excitation conditions, the sustained magnonic waves result in different characteristic dispersion diagrams suitable for different future ICT applications. Here, micromagnetic numerical simulations are important to interpret experimentally obtained dispersion relations as well as to predict the propagation properties under different conditions. To this end, we propose a new versatile simulation approach to determine the dispersion relations in magnonic structures in which we continuously excite the system at a fixed amplitude. Combining several simulations at different excitation frequencies, one can study the dispersion relation in the frequency range of interest without limits on the frequency resolution. This is very advantageous when one is aiming to study a specific spin wave mode or a bandgap in large detail. Moreover, by studying the magnetization response in the time domain, one can easily extract the temporal phase difference between the sustained magnonic waves on the one hand and the excitation at the other hand as well as the distinct mode profiles. We show that spin waves defining a magnonic band beat with a gradually varying phase differences with respect to the excitation. To show the applicability of the approach we apply it to three different classes of 2D magnonic crystals. Dispersion relations are determined or (i) a dotarray comprising closely interacting squares [1], (ii) an antidotarry defined by periodically placed circular holes in a Permalloy film [2] and (iii) a bicomponent crystal consisting of Permalloy and Cobalt squares arrangedin a chessboard pattern [3]. For the three classes, we validate the approach by comparing the simulation results with experimental data. [1] S. Tacchi et al., Phys. Rev. B 80, 024401 (2010). [2] R. Zivieri et al., Phys. Rev. B 85, 012403 (2012). [3] G. Gubbiotti et al. Appl. Phys. Lett. 100, 162407 (2012).I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
