Micromagnetic Simulation of Domain Walls in Exchange Spring Trilayers

Chiral domain wall structures in ferromagnetic exchange spring soft/hard/soft and hard/soft/hard trilayers were investigated with micromagnetic simulation, which enables us to fully characterize the nucleation and growth of buried domain walls in layered ferromagnetic thin films. Simulated results show that the trilayers are both exchange coupled and presenting chiral spin structures. Detailed features of field-dependent domain walls evolution in the spring magnets are also revealed. In process of remagnetization, the spin structure of soft/hard/soft is energetically more stable than that of hard/soft/hard