DOMAIN-WALL MOBILITY IN HIGH-UNIAXIAL-ANISOTROPY FERRITES

The dynamics of 180° domain walls has been studied in three hexagonal ferrite single crystals with a high uniaxial anisotropy. By means of an improved pulsed magnetic-field technique and by analysis of the experimental method, we can observe the single-wall mobility η just from the initial domain-wall motion, i.e., for the lowest values of the internal field Hi. In the examined ferrimagnetic oxides the initial domain-wall motion shows, as in cubic ferrites, a constant mobility η of the order of 102 cm/sec/Oe. Such a dynamical situation is followed by a more complex one, characterized by mobilities at least one order of magnitude lower. Moreover, we have indications that the domain-wall apparent mass increases with increasing wall acceleration. We discuss the above-mentioned phenomena in connection with the possible spin-wave excitation during the wall movement. © 1968 The American Institute of Physics.