The observation of domain structures in SmCo5by electron microscopy

In situ observations of the domain structure of SmCo
5
under changing magnetic field conditions have been carried out with a high-voltage electron microscope. These observations demonstrate the existence of some pinning processes and suggest that while pinning at crystallographic defects may have some significance, that at grain boundaries may be more important. Such a view is supported by the apparent disregard of domain walls for the majority of crystallographic defects which penetrate the homogenized material and the pinning observed at a grain boundary.