Shape Effect of Magnetoresistance Effect

The magnetoresistance of Ni-Co-Fe ternary alloy thin films, both circular and rectangular with varying widths, was studied. Sample resistivity was measured using a four-point probe. Using the method of images, the true value of ρ
_av
can be obtained for each film, but that of Δρ cannot, because the angle between the current direction and the magnetization direction is not uniform within the film. The behavior of ρ
_av
and Δρ can be explained exactly using the finite element method, enabling analysis of the magnetoresistance of films of various shapes.