Magnetic properties of compositionally modulated thin films (invited)

The magnetization density per cm³ of Ni-content of compositionally modulated Cu-Ni thin films at 5 K was found to depend on the modulation wavelength (λ) and amplitude (A) and reached ∼90% of that of pure Ni. Short-λ and low-T studies on Cu-Ni showed an inter-wavelength coupling of the moments of Ni-rich regions that may depend on the thickness of the latter relative to that of the Cu-rich regions. Evidence for xy-like two-dimensional ferromagnetism was also observed in Cu-Ni with λ containing only a few Ni-rich planes. Coercivity and anisotropy were found to depend strongly on the modulation characteristics; the former increased sharply with decreasing λ while the latter had an oscillatory dependence.