Spin polarization measurements in ferromagnetic SrRuO3 using point-contact Andreev reflection technique

Using the point-contact Andreev reflection (PCAR) technique, we have performed spin polarization measurements in a polycrystalline SrRuO3 to study the difference of the spin polarization between the ballistic and diffusive transport samples. PCAR spectra were measured with Nb tips for T = 4.2 K with changing the contact area mechanically. The results were well fitted by the modified Blonder-Tinkham-Klapwijk (mBTK) model. We estimate the spin polarization P ≈ 0.59, which is slightly larger than that of a single crystal film with P ≈ 0.51 due to the change of transport property.