DEPENDENCY OF COERCIVITY ON CO LAYER THICKNESS IN CO CU MULTILAYER STRUCTURES/

The magnetic and structural properties of Co/Cu multilayered film stru ctures were studied as a function of Co layer thickness to determine t he interrelationship between coercivity and ferromagnetic layer thickn ess. The nominal compositions of the films are NiFe(50 Angstrom)/Cu(25 00 Angstrom)/[Co(t)/Cu(50 Angstrom)](x), where t = 7, 10, 25, 50, 100 Angstrom for x = 20, and t = 200, 400, and 2000 Angstrom for x = 10, 5 , and 1, respectively. The measured coercivity correlates strongly wit h the changes in the local structural properties of the Co layers. Val ues were found to decrease with increasing t for t < 200 Angstrom in r esponse to the decreasing effect of surface and interface domain wall pinning. For t greater than or equal to 200 Angstrom coercivity values increase corresponding with the increased magnetocrystalline anisotro py associated with a transition in the Co layer from an fee state to a n hcp state.