Influence of the measurement frequency on the magnetic dissaccomodation spectra of YIG samples

C. TORRES; C. DE FRANCISCO; J. M. MUÑOZ; P. HERNÁNDEZ GÓMEZ; O. ALEJOS; P. G. BERCOFF; H. R. BERTORELLO

PHYSICA B - CONDENSED MATTER

Año: 2002 vol. 320 p. 264 - 266

0921-4526

Magnetic aftereffect phenomena in yttrium iron garnets and their relationship to the dynamics of domain walls are analyzed by means of the magnetic disaccommodation (DA) technique. The samples have been prepared using a standard ceramic technique in CO2 atmosphere in order to enhance the formation of ferrous ions in the lattice. The results reveal the presence of the well-known process II around 130K and a process at higher temperatures (187 K). Furthermore, accommodation (or negative DA) processes have been detected at temperatures just below process II. The features of these phenomena are strongly related to the measurement frequency and, hence, they are more noticeable as this frequency is increased. Such behavior is associated with the resonance of the domain wall motion at frequencies around the measurement frequency. The characteristic parameters that define this resonance depends upon time due to the presence of an induced anisotropy relaxation process that occurs after demagnetization.