Magnetic coupling in Fe/Cr/Fe(001) by spin-resolved empty-state spectroscopies

We report on a study of empty electronic states in Cr/Fe(001) films and a trilayer as obtained by means of spin-polarized inverse photoemission and absorbed current spectroscopies: both spectroscopies are sensitive to the magnetic character of the Fe film. In relatively thick ( >7 ML) Cr films, our data do not reveal any polarization dependence; on the contrary, in Fe/Cr/Fe(001), we observe a reversal of the magnetic ordering of the Fe overlayer with respect to the buried Fe substrate as a function of the Cr spacer thickness, confirming the oscillating transition from FM to AF coupling between the Fe layers.