Ce($x$Å)/Fe(20Å)

Figure: Normalised magnetisation vs temperature scans for Ce($x$Å)/Fe(20Å) multilayers.

Figure 7.5 shows the scans for Ce($x$Å)/Fe(20Å) multilayers. This set of scans has a fixed iron layer thickness of $20\ensuremath{\unskip\,\mathrm{\AA{}}}$.

The 20/20 and 27/20 samples have already been discussed. Both samples show antiferromagnetic coupling across the cerium layers. The 20/20 sample shows a mix of parallel and perpendicular moment alignment whilst the 27/20 sample shows perpendicular alignment.

The 40/20 sample shows either weak ferromagnetic or no coupling of the iron layers. It shows a similar temperature dependence to the 20/10 layer, with a small decrease in magnetisation with temperature of the ferromagnetically ordered iron layers far below their $T_{C}$ point. The iron layers in this sample have spins at most $10^{\circ}$ out of plane and only a $4\%$ reduction in hyperfine field compared to bcc iron, according to the Mössbauer measurements.

This set of data shows antiferromagnetic coupling for $20\ensuremath{\unskip\,\mathrm{\AA{}}}$ and $27\ensuremath{\unskip\,\mathrm{\AA{}}}$ cerium layers, and no or weak ferromagnetic coupling for $40\ensuremath{\unskip\,\mathrm{\AA{}}}$ layers.