Magnetic properties of amorphous Co0.74Si0.26/Si multilayers with different number of periods

Анотація

Two sets of [Co_0.74Si_0.26(5 nm)/Si(s)]_n amorphous films were prepared by magnetron sputtering: one in the form of multilayers with the Si spacer thickness s fixed at 3 nm, and the number of periods n varying from 1 to 10; and another one with only two periods and s varying from 3 to 24 nm (trilayers). In both series, the Co_0.74Si_0.26 layer thickness t was fixed at 5 nm. All the samples except the one with s = 24 nm demonstrate antiferromagnetic coupling. Their magnetic properties at room temperature were probed by magnetooptical transverse Kerr effect (MOTKE) and ferromagnetic resonance (FMR). The relative increase of the saturation magnetization M_s (for trilayers with respect to the one with s = 24 nm; for multilayers with respect to the single layer one) obtained from the FMR measurements was compared with the exchange coupling strength H_J^AF obtained from the MOTKE studies. H_J^AF and M_s dependencies vs n and s were found to be very similar to each other. Possible mechanisms of this similarity are discussed.