Thermally assisted manipulation of magnetic domain structures in amorphous rare-earth-Fe-B film

Abstract

The temperature dependence of domain evolution in amorphous rare-earth-Fe-B film is investigated via magnetic force microscopy as well as magnetization measurements. Within an external 1.0 kOe magnetic field perpendicular to the film, the domains evolve from stripes to bubbles as the temperature increases. Both of the domain wall motion and domain nucleation processes are found to be independent of the film defects. It leads to the formation of nearly perfect bubble domains with their sizes exhibiting a Gaussian distribution. If the external field is removed, the magnetic field generated by the scanning tip has to be taken into consideration. It is found that the tip field, although weak and localized, can modify the local domain structure within the scan area at 373 K. To explain the experimental results, we propose that the domain structure is usually stuck in one of the metastable states separated by energy barriers at a given temperature. The switching between different states is commonly governed by energy barriers and thermal activation, which could be partly controlled by the magnetic field and the temperature, respectively.