THE USE OF A MULTI-DOUBLE-CRYSTAL DIFFRACTOMETER TO INVESTIGATE NICKEL DOMAINS

The investigations of the domain structure in Ni single crystals is be st performed with a double-crystal diffractometer. Conventional small- angle instruments do not have the necessary angular resolution to dist inguish satellites of a main peak due to spin-dependent refraction of unpolarized neutrons by Bloch walls in Ni. With the help of a double-c rystal diffractometer operating with lamellae crystals as monochromato r and analyzer, the angular resolution is maintained but the intensity enhanced by a factor of 5.4. Within a series of measurements, it was possible to investigate Ni domains due to the high angular resolution of the new multi-double-crystal instrument and this improved intensity . The first results of the domain structure in [110] Ni single crystal s and a good estimation of the Bloch wall thickness are given.