Abstract
The interaction between superconductivity and ferromagnetism, which entails incompatible spin order, is one of the problems of fundamental interest in condensed-matter physics. In general, when a ferromagnet is placed in contact with a superconductor, the Cooper pairs from the superconductor are not expected to survive beyond at most a few nanometres into the ferromagnet. Here we present a systematic study of single-crystal ferromagnetic cobalt nanowires sandwiched between superconducting electrodes. Surprisingly, we find that a cobalt wire as long as 600 nm attains zero resistance at low temperatures. For even longer nanowires, the transition to incomplete superconductivity is foreshadowed by a strikingly large and sharp resistance peak near the superconducting transition temperature of the electrodes. Although the origin of the ‘critical peak’ remains mysterious, our analysis strongly points against charge or spin imbalance as its underlying cause.
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References
De Gennes, P. G. Boundary effects in superconductors. Rev. Mod. Phys. 36, 225–237 (1964).
van Dover, R. B., de Lozanne, A. & Beasley, M. R. Superconductor–normal–superconductor microbridges: Fabrication, electrical behaviour, and modelling. J. Appl. Phys. 52, 7327–7343 (1981).
Wang, J. et al. Proximity-induced superconductivity in nanowires: Minigap state and differential magnetoresistance oscillations. Phys. Rev. Lett. 102, 247003 (2009).
Buzdin, A. I. Proximity effects in superconductor–ferromagnet heterostructures. Rev. Mod. Phys. 77, 935–976 (2005).
Chiang, Yu. N., Shevchenko, O. G. & Kolenov, R. N. Manifestation of coherent and spin-dependent effects in the conductance of ferromagnets adjoining a superconductor. Low Temp. Phys. 33, 314–320 (2007).
Aumentado, J. & Chandrasekhar, V. Mesoscopic ferromagnet–superconductor junctions and the proximity effect. Phys. Rev. B 64, 054505 (2001).
Bergeret, F. S., Volkov, A. F. & Efetov, K. B. Odd triplet superconductivity and related phenomena in superconductor–ferromagnet structures. Rev. Mod. Phys. 77, 1321–1373 (2005).
Giroud, M., Courtois, H., Hasselbach, K., Mailly, D. & Pannetier, B. Superconducting proximity effect in a mesoscopic ferromagnetic wire. Phys. Rev. B 58, R11872–R11875 (1998).
Petrashov, V. T., Sosnin, I. A., Cox, I., Parsons, A. & Troadec, C. Giant mutual proximity effects in ferromagnetic/superconducting nanostructures. Phys. Rev. Lett. 83, 3281–3284 (1999).
Pena, V. et al. Coupling of superconductors through a half-metallic ferromagnet: Evidence for a long-range proximity effect. Phys. Rev. B 69, 224502 (2004).
Sosnin, I., Cho, H., Petrashov, V. T. & Volkov, A. F. Superconducting phase coherent electron transport in proximity conical ferromagnets. Phys. Rev. Lett. 96, 157002 (2006).
Keizer, R. S. et al. A spin triplet supercurrent through the half-metallic ferromagnet CrO2 . Nature 439, 825–827 (2006).
Bergeret, F. S., Volkov, A. F. & Efetov, K. B. Long-range proximity effects in superconductor–ferromagnet structures. Phys. Rev. Lett. 86, 4096–4099 (2001).
Tian, M. L. et al. Penetrating the oxide barrier in situ and separating freestanding porous anodic alumina films in one step. Nano Lett. 5, 697–703 (2005).
Hernandez-Ramirez, F. et al. Electrical properties of individual tin oxide nanowires contacted to platinum electrodes. Phys. Rev. B 76, 085429 (2007).
Kumar, N. et al. Investigation of superconductivity in electrochemically fabricated AuSn nanowires. Nanotechnology 19, 365704 (2008).
Tian, M. L. et al. Superconductivity and quantum oscillations in crystalline Bi nanowire. Nano Lett. 9, 3196–3202 (2009).
Sadki, E. S., Ooi, S. & Hirata, K. Focused-ion-beam-induced deposition of superconducting nanowires. Appl. Phys. Lett. 85, 6206–6208 (2004).
Li, W., Fenton, J. C., Wang, Y., McComb, D. M. & Warburton, P. A. Tunability of the superconductivity of tungsten films grown by focused-ion-beam direct writing. J. Appl. Phys. 104, 093913 (2008).
Schmidt, V. V. in The Physics of Superconductors: Introduction to Fundamentals and Applications (eds Muller, P. & Ustinov, A. V.) (Springer, 1997).
Tian, M. L. et al. Dissipation in quasi-one-dimensional superconducting single-crystal Sn nanowires. Phys. Rev. B 71, 104521 (2005).
Vila, L. et al. Transport and magnetic properties of isolated cobalt nanowires. IEEE Trans. Magn. 38, 2577–2579 (2002).
Brands, M. & Dumpich, G. Experimental determination of anisotropy and demagnetizing factors of single Co nanowires by magnetoresistance measurements. J. Appl. Phys. 98, 014309 (2005).
Santhanam, P., Shi, C. C., Wind, S. J., Brady, M. J. & Bucchignano, J. J. Resistance anomaly near the superconducting transition temperature in short aluminium wires. Phys. Rev. Lett. 66, 2254–2257 (1991).
Park, M., Isaacson, M. S. & Parpia, J. M. Resistance anomaly and excess voltage in inhomogeneous superconducting aluminium thin films. Phys. Rev. B 55, 9067–9076 (1997).
Arutyunov, K. Yu., Presnov, D. A., Lotkhov, S. V., Pavolotski, A. B. & Rinderer, L. Resistive-state anomaly in superconducting nanostructures. Phys. Rev. B 59, 6487–6498 (1999).
Tian, M. L. et al. Suppression of superconductivity in zinc nanowires by bulk superconductors. Phys. Rev. Lett. 95, 076802 (2005).
Zgirski, M., Riikonen, K., Touboltsev, V. & Arutyunov, K. Size dependent breakdown of superconductivity in ultranarrow nanowires. Nano Lett. 5, 1029–1033 (2005).
Wang, J. et al. Anomalous magnetoresistance oscillations and enhanced superconductivity in single-crystal Pb nanobelts. Appl. Phys. Lett. 92, 233119 (2008).
Bezryadin, A., Lau, C. N. & Tinkham, M. Quantum suppression of superconductivity in ultrathin nanowires. Nature 404, 971–974 (2000).
Ciurtois, H., Gandit, Ph. & Pannetier, B. Proximity-induced superconductivity in a narrow metallic wire. Phys. Rev. B 52, 1162–1166 (1995).
Jedema, F. J., van Wees, B. J., Hoving, B. H., Filip, A. T. & Klapwijk, T. M. Spin-accumulation-induced resistance in mesoscopic ferromagnet–superconductor junctions. Phys. Rev. B 60, 16549–16552 (1999).
Fal’ko, V. I., Volkov, A. F. & Lambert, C. Interplay between spin-relaxation and Andreev reflection in ferromagnetic wires with superconducting contacts. Phys. Rev. B 60, 15394–15397 (1999).
Soulen, R. J. Jr et al. Measuring the spin polarization of a metal with a superconducting point contact. Science 282, 85–88 (1998).
Piraux, L., Dubois, S., Fert, A. & Belliard, L. The temperature dependence of the perpendicular giant magnetoresistance in Co/Cu multilayered nanowires. Eur. Phys. J. B 4, 413–420 (1998).
Gueron, S., Pothier, H., Birge, N. O., Esteve, D. & Devoret, M. H. Superconducting proximity effect probed on a mesoscopic length scale. Phys. Rev. Lett. 77, 3025–3028 (1996).
Usadel, K. D. Generalized diffusion equation for superconducting alloys. Phys. Rev. Lett. 25, 507–509 (1970).
Ozatay, O. et al. Sidewall oxide effects on spin-torque- and magnetic-field-induced reversal characteristics of thin-film nanomagnets. Nature Mater. 7, 567–573 (2008).
Acknowledgements
This work was supported by the Penn State MRSEC under NSF grant DMR-0820404 and the Pennsylvania State University Materials Research Institute Nano Fabrication Network and the National Science Foundation Cooperative Agreement No. 0335765, National Nanotechnology Infrastructure Network, with Cornell University. We are grateful to P. A. Lee for helpful discussions. We thank J. Cardellino and D. Rench for magnetic force microscopy measurements.
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J.W., M.H.W.C. and M.T. planned the experiments. J.W., M.S., N.K. and B.L. carried out the experiments. J.W., M.H.W.C., C.S., J.K.J., N.S., M.T. and T.E.M. analysed the data.
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Wang, J., Singh, M., Tian, M. et al. Interplay between superconductivity and ferromagnetism in crystalline nanowires. Nature Phys 6, 389–394 (2010). https://doi.org/10.1038/nphys1621
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DOI: https://doi.org/10.1038/nphys1621
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