Robustness of Spin Polarization in Graphene-based Spin Valves

Decrease of spin polarization in spintronics devices under an application of bias voltage is one of currently important problems which should be solved. We reveal unprecedented robustness of spin polarization in multi-layer graphene spin valves at room temperature. Surprisingly, the spin polarization of injected spins is constant up to a bias voltage of +2.7 V and -0.6 V in positive and negative bias voltage applications, which is dramatically superior to all spintronics devices. Our finding is induced by suppression of spin scattering due to an ideal interface formation. Furthermore, we firstly report on important accordance between theory and experiment in molecular spintronics by observing the fact that signal intensity in a local scheme is double of that in a non-local scheme as theory predicts, which provides construction of a steadfast physical basis in this field.

[1]  Bruce W. Alphenaar,et al.  Coherent transport of electron spin in a ferromagnetically contacted carbon nanotube , 1999, Nature.

[2]  B. Wees,et al.  Electronic spin transport and spin precession in single graphene layers at room temperature , 2007, Nature.

[3]  B. V. van Wees,et al.  Anisotropic spin relaxation in graphene. , 2008, Physical review letters.

[4]  Ian Appelbaum,et al.  Electronic measurement and control of spin transport in silicon , 2007, Nature.

[5]  D. K. Young,et al.  Electrical spin injection in a ferromagnetic semiconductor heterostructure , 1999, Nature.

[6]  Transformation of spin information into large electrical signals using carbon nanotubes , 2005, Nature.

[7]  J. J. A. Baselmans,et al.  Electrical detection of spin precession in a metallic mesoscopic spin valve , 2002, Nature.

[8]  Masashi Shiraishi,et al.  Spin injection into a graphene thin film at room temperature , 2007 .

[9]  Etienne,et al.  Giant magnetoresistance of (001)Fe/(001)Cr magnetic superlattices. , 1988, Physical review letters.

[10]  Ian Appelbaum,et al.  Coherent spin transport through a 350 micron thick silicon wafer. , 2007, Physical review letters.

[11]  M. Nijboer,et al.  Spin injection and spin accumulation in all-metal mesoscopic spin valves , 2002, cond-mat/0207641.

[12]  S. Yuasa,et al.  Giant room-temperature magnetoresistance in single-crystal Fe/MgO/Fe magnetic tunnel junctions , 2004, Nature materials.

[13]  S. Yuasa,et al.  High Tunnel Magnetoresistance at Room Temperature in Fully Epitaxial Fe/MgO/Fe Tunnel Junctions due to Coherent Spin-Polarized Tunneling , 2004 .

[14]  B. Wees,et al.  Separating spin and charge transport in single-wall carbon nanotubes , 2005, cond-mat/0506538.

[15]  J. Moodera,et al.  Large spin diffusion length in an amorphous organic semiconductor. , 2008, Physical review letters.

[16]  S. Maekawa,et al.  Spin Current in Metals and Superconductors , 2008 .

[17]  B. V. van Wees,et al.  Electronic spin drift in graphene field-effect transistors. , 2008, Physical review letters.

[18]  P. Graziosi,et al.  Room-temperature spintronic effects in Alq3-based hybrid devices , 2008 .

[19]  A. Panchula,et al.  Giant tunnelling magnetoresistance at room temperature with MgO (100) tunnel barriers , 2004, Nature materials.

[20]  C. Adelmann,et al.  Electrical detection of spin transport in lateral ferromagnet–semiconductor devices , 2006, cond-mat/0701021.

[21]  Kinder,et al.  Large magnetoresistance at room temperature in ferromagnetic thin film tunnel junctions. , 1995, Physical review letters.

[22]  Masaya Nishioka,et al.  Spin transport through multilayer graphene , 2007 .

[23]  T. Miyazaki,et al.  Giant magnetic tunneling e ect in Fe/Al2O3/Fe junction , 1995 .

[24]  Binasch,et al.  Enhanced magnetoresistance in layered magnetic structures with antiferromagnetic interlayer exchange. , 1989, Physical review. B, Condensed matter.

[25]  Y. Aoyagi,et al.  Effect of probe configuration on spin accumulation in lateral spin-valve structure , 2005 .

[26]  H. Okada,et al.  High-quality and highly oriented graphite block from polycondensation polymer films , 1992 .