Magnetic Force Microscopy Study of Thermomagnetic Writing on Micron- and Submicron-Patterned TbFe Films Using Current Pulses

Thermomagnetic writing was successfully performed on microfabricated TbFe films with a perpendicular anisotropy by applying current pulses. The magnetic domain was imaged after every pulse by magnetic force microscopy (MFM) to determine the minimum current required for writing on patterned films of different sizes. For a constant pulse width, the dependence of the required minimum current on the surface area (A) of square-patterned films was measured and showed an A1/2 phenomenological variation. While it was also found that the current density and power density necessary for writing are invariable with the surface area of the patterned films for a given pulse width, and are about 5×106 A/cm2 and 0.3 mW/µm2, respectively, using a pulse width of 100 ns in the presence of a "writing" field of 100 Oe.