Magnetism of Fe Interface in Contact with Pd by Mössbauer Spectroscopy

Magnetic properties of Fe surface overcoated with Pd were investigated by means of 57 Fe Mössbauer spectroscopy. By UHV deposition, multilayer films were prepared, whose structures for instance were 56 Fe(70 Å)- 57 Fe(3.5 Å)-Pd, or 56 Fe(70 Å)- 57 Fe(3.5 Å)- 56 Fe(3.5 Å)-Pd. The hyperfine field at 4.2 K of the first surface layer was smaller than the bulk value. The spin direction was confirmed to be ferromagnetic. At 300 K, the first surface layer behaved paramagnetically and the exchange field was considered to be remarkably weak. On the other hand, the hyperfine fields of the next few layers were slightly larger than the normal value. A Friedel type oscillation of the surface magnetization was thus suggested.