Sd. Berry et al., MAGNETIZATION CHANGES WITH MODULATION PERIOD IN FE3O4 NIO SUPERLATTICES/, Journal of magnetism and magnetic materials, 123(1-2), 1993, pp. 126-132
We have magnetically characterized single crystal Fe3O4/NiO superlatti
ces grown on MgO(001), where the layer thickness has been varied over
a wide range. Hysteresis for modulation wavelength LAMBDA(mod) = 258 a
ngstrom is similar to bulk Fe3O4, while loops for LAMBDA(mod) < 80 ang
strom are nearly linear with applied field with minimal hysteresis and
remanence. The magnetization slopes of the latter are roughly proport
ional to LAMBDA(mod), and increase from 5 to 300 K. MeasurementS above
300 K suggest that both exchange coupling across NiO/Fe3O4 interfaces
and strain-induced variations in anisotropy, rather than paramagnetis
m, lead to this linear behavior.