title: Low temperature exchange bias in [DyFe(2)/YFe(2)] superlattices: effect of the thermo-magnetic preparation.
abstract: The effect of the thermo-magnetic preparation on exchange bias is investigated in an exchange-coupled [3 nm DyFe(2)/12 nmYFe(2)](22) superlattice. X-ray magnetic circular dichroism (XMCD) experiments at low temperature reveal that exchange bias originates from the quenched DyFe(2) magnetization, biasing the unpinned YFe(2) reversal. This quenched configuration can be tailored by changing the cooling field or the magnetic preparation at 300 K before zero-field cooling. Changing the amplitude of the cooling field induces interface domain walls and tends to modify the orientation of the pinning moments at the interfaces. This results in the observation of single loops and in the continuous variation of the bias field as a function of the cooling field. A specific magnetic preparation (field cycling) at 300 K induces different remanent states with lateral domains in the pinning layer, which remain unchanged at low temperature after zero-field cooling and behave independently. This gives rise to combined loops, whose shape reflects the domain populations.
authors.affiliation: Laboratoire de Physique des Matériaux (UMR CNRS 7556), Université H Poincaré-Nancy I, BP 239, 54506 Vandoeuvre les Nancy cedex, France.
authors.forename: K
authors.initials: K
authors.lastname: Dumesnil
authors.forename: C
authors.initials: C
authors.lastname: Dufour
authors.forename: S
authors.initials: S
authors.lastname: Fernandez
authors.forename: M
authors.initials: M
authors.lastname: Oudich
authors.forename: A
authors.initials: A
authors.lastname: Avisou
authors.forename: A
authors.initials: A
authors.lastname: Rogalev
authors.forename: F
authors.initials: F
authors.lastname: Wilhelm