PrCo/Co multilayer thin films have been prepared by sputtering. After
heat treatment, high coercivity is developed and the remanence is enha
nced for the insertion of the Co layers and the exchange coupling betw
een the hard phase and the soft phase, which leads to high energy prod
ucts of the composite magnets. The nanostructure of the films has been
studied by TEM. It is found that the grain size of the films with hig
h energy products is in the range from 10 to 25 nanometers.