Effects of the biquadratic exchange coupling on the localization and scaling laws of spin waves in Fibonacci superlattices

In this paper we study the spin wave spectra of quasiperiodic magnetic superlattices following a Fibonacci sequence. We consider superlattices that are composed of two simple cubic ferromagnetic materials which interact by bilinear and biquadratic exchange couplings at the interfaces. A transfer matrix treatment is employed with the calculations carried out for the exchange dominated regime within the framework of the Heisenberg model and taking into account the random phase approximation (RPA). The numerical results obtained show the effects of the biquadratic exchange coupling on the localization and scaling laws of the spin wave bulk bands.