Spin-polarized tunneling spectroscopy in tunnel junctions with half-metallic electrodes -: art. no. 137203

We have studied the magnetoresistance (TMR) of tunnel junctions with electrodes of La2/3Sr1/3 MnO3 and we show how the variation of the conductance and TMR with the bias voltage can be exploited to obtain precise information on the spin and energy dependence of the density of states. Our analysis leads to a quantitative description of the band structure of La2/3Sr1/3 MnO3 including the energy gap delta between the Fermi level and the bottom of the t(2g) minority-spin band, in good agreement with data from spinpolarized inverse photoemission experiments. This shows the potential of magnetic tunnel junctions with half-metallic electrodes for spin-resolved spectroscopic studies.