Magnetic properties of lithographically defined rectangular antidot permalloy arrays

We have investigated the magnetic properties of rectangular antidot (2 x 10 mu m(2)) arrays embedded into 80 nm thick continuous permalloy films with the inter-hole spacing of 2 and 6 mu m. We observed that the presence of the rectangular hole structures strongly modifies the shape of M-H loops, when compared with the reference continuous film. Specifically, the coercivity increases drastically as the inter-hole spacing is reduced. This is in agreement with our magnetic force microscopy images. Marked changes in both the shape and sign of the magnetoresistance curve were also observed. (C) 2003 Elsevier B.V. All rights reserved.