Influence of Co layer thickness on the structural and magnetic properties of multilayers

International audienceThe correlated effects of the insertion of a Pt spacer between ferromagnetic and antiferromagnetic layers and of the variation of the Co layers thickness on the structural and magnetic properties of [ (Pt/Co tCo) 3 /Pt tPt /IrMn ] n multilayers have been studied. Samples with n = 1 and 7, t Co = 0.4 and 0.6 nm, t Pt = 0 and 0.4 nm have been investigated by tomographic atom probe and superconducting quantum interference device magnetometry. For spacer free samples (t Pt = 0), the structural investigation shows that when t Co = 0.4 nm, Mn and Ir atoms diffuse deeply in the (Pt/Co) multilayers. In contrast for t Co = 0.6 nm, the Mn and Ir diffusion is much reduced. Because Pt acts as a barrier against the Mn and Ir diffusion, this difference is less pronounced in samples with Pt insertion. The hysteresis loops shapes, the exchange bias fields and the saturation magnetization values were correlated with the structural properties of these samples and discussed, taking into account the susceptibility, exchange stiffness, and perpendicular magnetic anisotropy

Bimodal distribution of blocking temperature in exchange-biased ferromagnetic/antiferromagnetic bilayers

International audienceThe blocking temperature TB distribution of various polycrystalline ferromagnetic F/antiferromagnetic AF bilayers exhibits two distinct peaks. This is ascribed to the existence of two families of magnetic entities determining the temperature dependence of exchange bias. One is formed by the AF grains which undergo thermally activated magnetic reversal. The other is formed by F/AF disordered interfacial spins which exhibit spin-glass-like behavior. The bulk versus interfacial nature of these two families is indicated by the dependence of the TB distribution on the AF thickness

Characterization of (Pt2 nm/Co0.4 nm)3/Ptx/IrMn7 nm multilayers by tomographic atom probe: On the role of a Pt spacer

International audienceStructural investigation of Ta 3 nm / Pt 2 nm / Co 0.4 nm 3 / Pt x / IrMn 7 nm 7 / Pt 10 nm multilayers without x =0 nm and with x = 0.4 nm a Pt spacer has been performed by laser-assisted tomographic atom probe. Without a Pt spacer a strong intermixing is observed at the Co/IrMn interface. In the multilayer containing a Pt spacer the Co/Pt/IrMn interface is very weakly intermixed. It thus appears that the Pt spacer acts as a diffusion barrier that prevents the Ir and Mn atoms from diffusing into the Co layer. The consequences of this effect on the magnetic properties are discussed. The exchange bias field and the anisotropy direction of these two multilayers are analyzed and correlated with the structural investigation

Structural analysis and magnetic properties of ( Pt / Co ) 3 / Pt tPt / IrMn multilayers

International audienceStructural and magnetic investigations of Ta 3 nm / Pt 2 nm / Co 0.4 nm 3 / Pt tPt / IrMn 7 nm 7 / Pt 10 nm multilayers with t Pt = 0 and t Pt = 0.4 nm have been carried out using x-ray reflectometry, tomographic atom probe, and superconducting quantum interference device magnetometry. The structural investigations show that the Co/ IrMn interface is more diffuse in the absence of the Pt spacer. The consequences on the magnetic properties are discussed. The exchange-bias field and the anisotropy direction of these two specimens are analyzed in comparison to Ta 3 nm / Pt 2 nm / Co 0.4 nm 3 / Pt tPt / IrMn 7 nm / Pt 10 nm multilayers containing only one ferromagnetic/ antiferromagnetic repeat and correlated with the structural investigations

Temperature stability of (Pt/Co) 3 /IrMn multilayers

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