Tuning the coercive field of CoFe₂ in hard/soft CoFe₂O₄/CoFe₂ bilayers

Abstract

The sensitivity of magnetoresistive devices, i.e. their ability to be switched by very small fields, depends on the softness of their soft electrode. In this paper, we show the possibility to tune the coercive field of the CoFe2 alloy, commonly used as a soft electrode, from intrinsic values down to zero, by varying the pulsed laser ablation conditions of CoFe2/CoFe2O4 bilayers. This tuning possibility relies on the existence of a frustration of the spins of the CoFe2 layer originating from both the ferrimagnetic nature of the CoFe2O4 layer and the oxide/metal interface roughness.