Tunneling Magnetoresistance Simulation Used to Detect Domain-Wall Structures and Their Motion in a Ferromagnetic Wire

Devices consisting of single or double magnetic tunnel junctions (MTJs) with cross-magnetization configurations were proposed to enable simultaneous electrical detection of both the structure and motion of a domain wall (DW), and the operation of these devices was confirmed through micromagnetic simulation. Through the tunnel magnetoresistance (TMR) effect of the MTJs, two types of domain-wall structure formed in a ferromagnetic wire were clearly identified: a transverse wall (TW) in which the magnetization at the center of the wall is directed transverse to the wire axis, and a vortex wall (VW) in which the magnetization circulates in the plane about a small perpendicular vortex core. In addition to the structural difference between TW and VW, the velocity of the DW motion was detected through the time response of the TMR.