Magnetization reversal process of submicrometer-scale hall bars of ferromagnetic semiconductor p-In_0.97Mn_0.03As

The magnetization reversal process of submicrometer-scale Hall bars of the ferromagnetic semiconductor p-In_0.97Mn_0.03As has been investigated by measuring the Hall resistivity with changing the direction of the applied magnetic field. The angle dependence of the coercive force indicates that the magnetization reversal process is more likely governed by the magnetic domain wall displacement. Furthermore, observation of several Barkhausen jumps on a 0.7-μm-wide Hall bar makes it clear that p-Ino_0.97Mn _0.03As has a small-domain-sized multidomain structure near the coercive force. It is also shown that p-In_0.97Mn_0.03As has an ideal uniaxial magnetic easy axis perpendicular to the plane. The magnetization reversal process of p-In_0.97Mn_0.03As is distinct from that of a similar ferromagnetic semiconductor p-Ga _1-xMn_xAs.