In this article, on page 1683, left column, last paragraph the sentence 'The substrate was covered with a 50 nm layer of silver, a 150 nm layer of permalloy Ni80Fe20 and 20 nm layer of silicon nitride should have read 'The substrate was covered with a 100 nm layer of silver, a 70 nm layer of permalloy Ni80Fe20, and 15 nm layer of silicon nitride.