In Situ Observation of Domain Wall Pinning in Sm(Co,Fe,Cu,Zr)_z Magnet by Lorentz Microscopy

摘要

The microstructure and magnetic domain-wall motion of a sintered Sm(Co,Fe,Cu,Zr) permanent magnet with different Cu and Fe contents was investigated by Lorentz transmission electron microscopy. The domain-wall motion under different magnetic fields indicates that most domain walls are strongly attracted by the SmCo boundary phases, but some of them are repulsed to the SmCo cell phase. Differences in Cu and Fe distribution at the SmCo cell boundary phase and the SmCo5/SmCo interface are considered to result in domain-wall behavior, and a larger Cu and a smaller Fe content in the sample make the attractive pinning force stronger and, therefore, coercivity is higher.