X-ray photoelectron spectroscopy study of an exchange bias system on the basis of Co70Fe30/Mn83Ir17 interface

The consequences of 10 keV He+ ion bombardment on exchange biased Cu(50 nm)/Mn83Ir17(10 nm)/Co70Fe30(6.5 nm)/Ta(15 nm) thin film systems are studied by X-ray photoelectron spectroscopy. The modifications of the exchange bias field, the elemental depth concentration profiles, and the phase composition of the Mn83Ir17/Co70Fe30 interface zone have been investigated for selected doses. Measured atomic depth concentration profiles confirmed a broadening of the interface zone between ferromagnetic and antiferromagnetic layers upon bombardment; the width of the interface zone correlates with the relative change of the exchange bias field. The profiles of the Mn2p and Mn3s photoelectron peaks revealed the presence of a non-Mn83Ir17 phase containing quasiatomic manganese with mean local spin and magnetic moments greater than those in Mn within the Mn83Ir17 alloy in the interface zone. The magnitude of the exchange bias field correlates with the amount of manganese in this high-spin-Mn phase.