Abstract: Because the spin-flip length is longer than the electron mean-free-path in a metal, past studies of spin-flip scattering were limited to the diffusive regime. We have developed a method that uses a magnetic double barrier tunnel junction to study spin flip scattering in nanometer sized spacer layers near the ballistic limit. We extract the voltage and temperature dependence of the spin-flip conductance Gs in the spacer layer from magnetoresistance measurements. In addition to spin scattering information, such as the mean-free-path (70nm) and the spin-flip length (1.0—2.6μm) at 4.2K, this technique also yields information on the density of states and quantum well resonance in the spacer layer.