Magnetic hyperfine fields in ultrathin Ni films on Cu(100)

Abstract

The magnetic hyperfine field was measured at 111In(111Cd) probe atoms in ultrathin Ni films epitaxially grown on Cu(100) utilizing the perturbed γγ-angular correlation (PAC) method. The behaviour of the hyperfine field as a function of temperature was studied for different film thicknesses ranging from 2 up to 10 monolayers. It was found that the strength of the hyperfine fields as well as the critical temperatures are strongly reduced for thin nickel films and approach the bulk value with increasing film thickness. The orientation of the hyperfine field is discussed.