A Mossbauer study of Fe(5 Å)+Cu(50 Å) multilayers

Recent magnetic viscosity studies of Fe/Cu multilayer systems containing 5 Å layers of Fe sandwiched between 50 Å layers of Cu(111) have shown behaviour that is consistent with macroscopic quantum tunnelling of the magnetization. As part of a wider program of measurements aimed at characterising this system, ⁵⁷Fe Mossbauer spectra of two samples grown in different laboratories were recorded at temperatures ranging from room temperature to 4.2 K, and at 4.2 K in applied fields of up to 5 T. The Mossbauer data show that one sample contains iron oxide impurities, but that both samples contain roughly equal quantities of ferromagnetic BCC Fe and antiferromagnetic FCC Fe. The Fe moments in both the BCC and FCC phases lie preferentially in the plane of the multilayer film