Effect of exchange springs on the coercivity of DyFe2–YFe2 superlattices

Abstract The coercivity of MBE-grown Laves-phase DyFe 2 –YFe 2 thin-layered (⩽50 A) superlattice samples, with a (1 1 0) growth direction, can be varied by adjusting the relative thickness of the YFe 2 and DyFe 2 layers. However, for sufficiently thick layers, the coercivity is found to be dependent on the thickness of the YFe 2 layers, even when the ratio of DyFe 2 /YFe 2 is fixed. This feature is illustrated using the superlattice films [ w DyFe 2 / w YFe 2 ]×40, with w =75, 100 and 150 A. The underlying reason for the decrease in coercivity with increasing width w , is traced to the action of the magnetic exchange springs in the YFe 2 layers.