Investigation of ferromagnetic microstructures as electrodes for spin-polarized transport experiments

Patterned ferromagnetic structures are intended as electrodes to drive a sp in-polarized current through the quasi two-dimensional electron system of a semiconductor. To utilize such structures in transport experiments it is i mportant to know their micromagnetic behavior. We have prepared Permalloy e lectrodes for the ballistic transport regime by electron-beam lithography o n InAs single crystals. Using magnetic-force microscopy we measure the magn etization configurations at zero external magnetic fields. Micromagnetic si mulations verify that the observed magnetization states are the energetical ly most favorable ones. In addition, the micromagnetic behavior in external magnetic fields is simulated. (C) 2001 American Institute of Physics.