Effect of the Ferromagnetic Layer Thickness on the Blocking Temperature in IrMn/CoFe Exchange Couples

In this work we present a study of the thermal stability of IrMn/CoFe exchange couples as a function of the thickness of the ferromagnetic (F) layer t
_F
. We find a monotonic decrease in the average blocking temperature (T
_B
) with t
_F
of up to 29% for t
_F
= 12 nm. We have quantified the effect of the exchange field (H*) from the F layer on the antiferromagnetic (AF) layer and its effect on the thermal stability of the AF. H* can increase the degree of thermal activation by up to 44%.