We study conductance and spin-polarization fluctuations in one-dimensional wires with spin-5/2 magnetic impurities (Mn). Our tight-binding Green function approach goes beyond the mean field thus including s-d exchange-induced spin-flip scattering. In a certain parameter range, we find that spin-flip suppresses conductance fluctuations while enhancing spin-polarization fluctuations. More importantly, spin-polarization fluctuations attain a universal value 1/3 for large enough spin-flip strengths. This intrinsic spin-polarization fluctuation may pose a severe limiting factor to the realization of steady spin-polarized currents in Mn-based one-dimensional wires.
Bibliographical noteCopyright (2002) American Physical Society
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