Interfacial magnetic anisotropy in a Pt/CO1-xFex/Pt multilayer is tuned by doping iron atoms into the cobalt layer. The perpendicular magnetic anisotropy and out-of-plane coercivity are found to decrease with increasing x. For a specific x, the out-of-plane coercivity acquires a maximal value as a function of the thickness of the CoFe layer. At low temperature, the coercivity is enhanced. Small coercivity but reasonably large perpendicular magnetic anisotropy can be obtained by controlling the x and CoFe layer thickness.
Polycrystalline BiFe_(1-x)Mn_(x)O_(3) films with x up to 0.50 are prepared on LaNiO3 buffered surface oxidized Si substrates.The doped Mn is confirmed to be partially in a+4 valence state.A clear exchange bias effect is observed with a 3.6 nm Ni_(81)Fe_(19) layer deposited on the top BiFe_(1-x)Mn_(x)O_(3) layer,which decreases drastically with increasing Mn doping concentration and finally to zero when x is above 0.20.These results clearly demonstrate that the exchange bias field comes from the net spins due to the canted antiferromagnetic spin structure in polycrystalline BiFe_(1-x)Mn_(x)O_(3) films,which transforms to a collinear antiferromagnetic spin structure when the Mn doping concentration is larger than 0.20.
A significant exchange bias （EB） traimng ettect has been observea in sputter deposited FeAu/FeNi bilayers, wherein the exchange field （HE） exhibits a special sign-changeable temperature dependence. Very interestingly, despite the absence of multiple easy axes in the FeAu spin glass （SG） layer, HE drops abruptly between the first and second magnetic cycles, which is followed by a more gradual continuous change in the subsequent cycles. This training behavior cannot be described by the empirical n-1/2 law because of the asymmetric magnetization reversal processes. We propose modifying Binek＇s model to include the asymmetric changes of the pinning SG spins at the descending and ascending branches. This new model successfully describes the EB training effect in FeAu/FeNi bilayers.
