Heat-assisted magnetization switching in elongated submicrometer Permalloy structures

The effect on switching behavior of locally heating individual Permalloy nanostructures is reported. The samples consisted of isolated magnetic structures with an aluminum conducting strip on top at one end of each structure, through which direct current passed to heat the nanostructure. Magnetization switching in individual nanostructures was detected using the magneto-optic Kerr effect. The average coercivity fell with increasing current in the aluminum strip by up to 20%, but, interestingly, the change in absolute magnitude of the coercivity was similar for nanowires of different width for current densities approaching 10(11) A m(-2) in the aluminum conductor. The temperature rise at this current density is less than 40 K. (C) 2004 American Institute of Physics.