Finite-size effects in amorphous Fe sub(90)Zr sub(10)/Al sub(75)Zr sub(25) multilayers

The thickness dependence of the magnetic properties of amorphous Fe sub(90) Zr sub(10) layers is explored using Fe sub(90) Zr sub(10)/Al75 Zr sub(25) multilayers. The Al sub(75) Zr sub(25) layer thickness is kept at 40 [Angstrom], while the thickness of the Fe sub(90) Zr sub(10) layers is varied between 5 and 20 [Angstrom]. The thickness of the Al sub(75) Zr sub(25) layers is sufficiently large to suppress any significant interlayer coupling. Both the Curie temperature and the spontaneous magnetization decrease nonlinearly with decreasing thickness of the Fe sub(90) Zr sub(10) layers. No ferromagnetic order is observed in the multilayer with 5-[Angstrom] Fe sub(90) Zr sub(10) layers. The variation of the Curie temperature T sub(c) with the Fe sub(90) Zr sub(10) layer thickness t is fitted with a finite-size scaling formula [1 - T sub(c) (t)/T sub(c) ([infinity])] = [(t - t')/t sub(0)] super(-[lambda]), yielding [lambda] = 1.2, and a critical thickness t' = 6.5 [Angstrom], below which the Curie temperature is 0.