Element-specific magnetometry with photoelectron dichroism: FeCo and FeNi

We have investigated fee FexCo1-x and FexNi1-x alloys grown on Cu(100) with X-ray magnetic linear dichroism angular distributions in photoemission (XM LDAD). To achieve this end, a simple model has been developed, which accura tely describes the experimental spectra and supports our application of XML DAD as a form of elementally specific magnetometry. This model combines the simplicity and physical insight of a single-electron picture with multiele ctronic effects, via the utilization of "Doniach-Sunjic" lineshapes for eac h component within the Fe 3p multiplet. We will also briefly discuss the ob served fine structure in the emission of the Fe 3p core level, which was pr eviously predicted but lacking experimental confirmation. We have found dif ferent behavior for the dichroism of the Fe 3p level at high and low Fe con centrations upon alloying with Co, compared to alloying with Ni. These cont rasting observations can be explained in part by the different behavior of the atomic volume. Both systems show also a change of the in-plane easy axi s upon increasing the Fe content. For small concentrations the easy axis is along the {011} direction, which changes to the {001} direction at a highe r Fe content. Interestingly the actual transition occurs in both instances at roughly the same electron/atom count. Published by Elsevier Science B.V.