有限フェリ磁性体としてのFe/Cr人工格子の磁性  [in Japanese] Magnetism of Fe/Cr Multilayers Considered as Finite-Size Ferrimagnets  [in Japanese]

The magnetization processes of antiferromagnetically coupled Fe/Cr multilayers with two Fe layer thicknesses, such as [Fe(40Å)/Cr(10Å)/Fe(20Å)/Cr(10Å)]_N were studied. These multilayers can be considered as artificial ferrimagnets with finite numbers of layers. There are substantial differences between the magnetization processes for multilayers with even and odd numbers of Fe layers, when the magnetic field is applied along the easy axis. Because of the finite number of Fe layers, multilayers with even numbers of Fe layers show the surface spin-flop transition before the bulk spin-flop with increasing mgneitc field, since the end Fe layers are subject to half the exchange coupling of the inner Fe layers. By measurement of the magnetization curve and the field dependence of the magnetic torque, the spin-flop transition for samples was investigated, and the exchange-coupling energy in samples with 2,3, and 5 Fe layers was directly evaluated.