Magnetization distributions in thin film Permalloy strips

摘要

Thin film Permalloy strips are used extensively for magnetoresistive sensors both in magnetometry and magnetic recording. A determination of magnetization distributions is vital to allow optimization of sensor performance. Results from a previously described scanning laser microscope (SLM) unambiguously determine magnetization distributions to submicron resolution. Operating the SLM in a mode sensitive to magnetization angles about the long axis of the strip shows typical closure domains. If the mode is sensitive to fluctuations about the strip short axis then light and dark bands are observed. These results indicate that the magnetization is not parallel with the strip edges within the domains as normally considered for closure domains. The SLM images are compared with results from a previously described numerical micromagnetic model. Results from the model compare well with those from the SLM, confirming the ability of the model to reliably predict domain activity in Permalloy strips. Results are shown for Permalloy strips of approximately 15 mgr;mtimes;50 mgr;m and 250 Aring; thick in the presence of dc and ac magnetic fields.