ABSTRACT Spin injection and accumulation are key phenomena supporting a variety of concepts for spin-electronic devices. These phenomena are expected to be enhanced in nanoparticles over

bulk structures due to their discrete energy levels and large charging energies. In this article, precise magnetotransport measurements in the single-electron tunnelling regime are performed

by preparing appropriate microfabricated devices containing cobalt nanoparticles. Here we provide experimental evidence for characteristic features of spin accumulation in magnetic

nanoparticles, such as oscillations of the magnetoresistance with a periodical sign change as a function of bias voltage. Theoretical analysis of the magnetoresistance behaviour clearly

$21.58 per issue Learn more Buy this article * Purchase on SpringerLink * Instant access to full article PDF Buy now Prices may be subject to local taxes which are calculated during checkout

ADDITIONAL ACCESS OPTIONS: * Log in * Learn about institutional subscriptions * Read our FAQs * Contact customer support SIMILAR CONTENT BEING VIEWED BY OTHERS GIANT CHARGE-TO-SPIN

CONVERSION IN FERROMAGNET VIA SPIN-ORBIT COUPLING Article Open access 29 October 2021 VERDAZYL RADICAL POLYMERS FOR ADVANCED ORGANIC SPINTRONICS Article Open access 14 January 2025 OXYGEN

VACANCY-DRIVEN SPIN-TRANSFER TORQUE ACROSS MGO MAGNETIC TUNNEL JUNCTIONS Article Open access 07 January 2025 REFERENCES * Prinz, G. A. Magnetoelectronics. _Science_ 282, 1660–1663 (1998).

Article  CAS  Google Scholar  * Wolf, S. A. et al. Spintronics: A spin-based electronics vision for the future. _Science_ 294, 1488–1495 (2001). Article  CAS  Google Scholar  * Johnson, M.

& Silsbee, R. H. Interfacial charge-spin coupling: Injection and detection of spin magnetization in metals. _Phys. Rev. Lett._ 55, 1790–1793 (1985). Article  CAS  Google Scholar  *

Jedema, F. J., Filip, A. T. & van Wees, B. J. Electrical spin injection and accumulation. _Nature_ 410, 345–348 (2001). Article  CAS  Google Scholar  * Jedema, F. J., Heersche, H. B.,

Filip, A. T., Baselmans, J. J. A. & vanWees, B. J. Electrical detection of spin precession in a metallic mesoscopic spin valve. _Nature_ 416, 713–716 (2002). Article  CAS  Google Scholar

  * Grabert, H. & Devoret, M. H. (eds) _Single Charge Tunneling_ vol. 294 of _NATO ASI Series_ (Plenum, New York, 1992). Google Scholar  * Ono, K., Shimada, H., Kobayashi, S. &

Ootuka, Y. Magnetoresistance of Ni/NiO/Co small tunnel junctions in Coulomb blockade regime. _J. Phys. Soc. Jpn_ 65, 3449–3451 (1996). Article  CAS  Google Scholar  * Mitani, S. et al.

Enhanced magnetoresistance in insulating granular systems: Evidence for higher-order tunneling. _Phys. Rev. Lett._ 81, 2799–2802 (1998). Article  CAS  Google Scholar  * Yakushiji, K. et al.

Enhanced tunnel magnetoresistance in granular nanobridges. _Appl. Phys. Lett._ 78, 515–517 (2001). Article  CAS  Google Scholar  * Yakushiji, K., Mitani, S., Takanashi, K. & Fujimori, H.

Tunnel magnetoresistance oscillations in current perpendicular to plane geometry of CoAlO granular thin films. _J. Appl. Phys_ 91, 7038–7040 (2002). Article  CAS  Google Scholar  * Barnas̀,

J. & Fert, A. Magnetoresistance oscillations due to charging effects in double ferromagnetic tunnel junctions. _Phys. Rev. Lett._ 80, 1058–1061 (1998). Article  Google Scholar  *

Barnas̀, J. & Fert, A. Effect of spin accumulation on single-electron tunneling in a double ferromagnetic microjunction. _Europhys. Lett._ 44, 85–90 (1998). Article  Google Scholar  *

Brataas, A., Nazarov, Y. V., Inoue, J. & Bauer, G. E. W. Spin accumulation in small ferromagnetic double-barrier junctions. _Phys. Rev. B_ 59, 93–96 (1999). Article  CAS  Google Scholar

  * Barthélémy, A., Fert, A. & Petroff, F. in _Handbook of Magnetic Materials_ vol. 12 (ed. Buschow, K. H. J.) (Elsevier, Amsterdam, 1999). Google Scholar  * Bass, J. & Pratt Jr, W.

Current-perpendicular (CPP) magnetoresistance in magnetic metallic multilayers. _J. Magn. Magn. Mater._ 200, 274–289 (1999). Article  CAS  Google Scholar  * Maekawa, S. & Shinjo, T.

(eds) _Spin Dependent Transport in Magnetic Nanostructures_ (Advances in Condensed Matter Science series, Taylor & Francis, London and New York, 2002). Google Scholar  * Mitani, S.,

Fujimori, H. & Ohnuma, S. Spin-dependent tunneling phenomena in insulating granular systems. _J. Magn. Magn. Mater._ 165, 141–148 (1997). Article  CAS  Google Scholar  * Yakushiji, K.,

Mitani, S., Takanashi, K., Ha, J.-G. & Fujimori, H. Composition dependence of particle size distribution and giant magnetoresistance in Co-Al-O granular films. _J. Magn. Magn. Mater._

212, 75–81 (2000). Article  CAS  Google Scholar  * Weymann I. & Barnas̀, J. Transport characteristics of ferromagnetic single-electron transistors. _Phys. Status Solidi B_ 236, 651–660

(2003). Article  CAS  Google Scholar  * Slonczewski, J. C. Conductance and exchange coupling of two ferromagnets separated by a tunneling barrier. _Phys. Rev. B_ 39, 6995–7002 (1989).

Article  CAS  Google Scholar  * Inoue, J. & Maekawa, S. Theory of tunneling magnetoresistance in granular magnetic films. _Phys. Rev. B_ 53, R11927–R11929 (1996). Article  CAS  Google

Scholar  * Brataas, A., Nazarov, Y. V. & Bauer, G. E. W. Finite-element theory of transport in ferromagnetic-normal metal systems. _Phys. Rev. Lett._ 84, 2481–2484 (2000). Article  CAS 

Google Scholar  * Hernando, D. H., Nazarov, Y. V., Brataas, A. & Bauer, G. E. W. Conductance modulation by spin precession in noncollinear ferromagnet normal-metal ferromagnet systems.

_Phys. Rev. B_ 62, 5700–5712 (2000). Article  Google Scholar  * Kübler, J. _Theory of Itinerant Electron Magnetism_ (Oxford Univ. Press, New York, 2000). Google Scholar  * Stearns, M. B.

Simple explanation of tunneling spin-polarization of Fe, Co, Ni and its alloys. _J. Magn. Magn. Mater._ 5, 167–171 (1977). Article  CAS  Google Scholar  * Meservey, R. & Tedrow, P.

Spin-polarized electron tunneling. _Phys. Rep._ 238, 173–243 (1994). Article  Google Scholar  * Guéron, S., Deshmukh, M. M., Myers, E. B. & Ralph, D. C. Tunneling via individual

electronic states in ferromagnetic nanoparticles. _Phys. Rev. Lett._ 83, 4148–4151 (1999). Article  Google Scholar  * Dechmukh, M. M. et al. Magnetic anisotropy variations and nonequilibrium

tunneling in a cobalt nanoparticle. _Phys. Rev. Lett._ 87, 226801 (2001). Article  Google Scholar  * Kleff, S., von Delft, J., Deshmukh, M. M. & Ralph, D. C. Model for ferromagnetic

nanograins with discrete electronic states. _Phys. Rev. B_ 64, 220401R (1999). Article  Google Scholar  * Kawabata, A. Electronic properties of fine metallic particles. III. E. S. R.

absorption line shape. _J. Phys. Soc. Jpn_ 29, 902–911 (1970). Article  CAS  Google Scholar  * Khalliulin, G. G. & Khusainov, M. G. Theory of spin-lattice relaxation of conduction

electrons in small metallic particles. _Sov. Phys. JETP_ 67, 524–529 (1988). Google Scholar  * Mitrikas, G., Trapalis, C. C. & Kordas, G. Electron spin-lattice relaxation of silver

nanoparticles embedded in SiO2 and TiO2 matrices. _J. Chem. Phys._ 111, 8098–8104 (1999). Article  CAS  Google Scholar  * Yakushiji, K., Mitani, S., Takanashi, K. & Fujimori, H. Bias

voltage dependence of GMR in insulating granular thin films. _J. Magn. Soc. Jpn_ 22, 577–580 (1998). Article  CAS  Google Scholar  Download references ACKNOWLEDGEMENTS We thank G. G.

Khalliulin and J. Martinek for useful discussions. Some of the experiments were performed at LAM, IMR, Tohoku University. K. T. and S. Mitani were supported by the Asahi glass foundation. S.

Mitani was supported by the Sumitomo Foundation. F.E. was supported by the 21st century COE program for young researchers. F.E. is grateful to the Post-doctoral fellowship program of JSPS.

H.I. is supported by MEXT. Kakenhi (No. 14076204 and 16710061). H.I., S.T. and S.Maekawa were supported by the NAREGI Nanoscience Project. AUTHOR INFORMATION AUTHORS AND AFFILIATIONS *

Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, 980-8577, Sendai, Japan Kay Yakushiji, Franck Ernult, Kazutaka Yamane, Seiji Mitani, Koki Takanashi, Saburo

Takahashi & Sadamichi Maekawa * CREST, Japan Science and Technology Agency, 4-1-8 Honcho,, Kawaguchi, 332-0012, Japan Kay Yakushiji, Hiroshi Imamura, Seiji Mitani, Koki Takanashi, Saburo

Takahashi, Sadamichi Maekawa & Hiroyasu Fujimori * Graduate School of Information Sciences, Tohoku University, Aramaki,, Aoba-ku, 980-8579, Sendai, Japan Hiroshi Imamura * The Research

Institute for Electric and Magnetic Materials, 2-1-1 Yagiyama-minami, Taihaku-ku, 982-0807, Sendai, Japan Hiroyasu Fujimori Authors * Kay Yakushiji View author publications You can also

search for this author inPubMed Google Scholar * Franck Ernult View author publications You can also search for this author inPubMed Google Scholar * Hiroshi Imamura View author publications

You can also search for this author inPubMed Google Scholar * Kazutaka Yamane View author publications You can also search for this author inPubMed Google Scholar * Seiji Mitani View author

publications You can also search for this author inPubMed Google Scholar * Koki Takanashi View author publications You can also search for this author inPubMed Google Scholar * Saburo

Takahashi View author publications You can also search for this author inPubMed Google Scholar * Sadamichi Maekawa View author publications You can also search for this author inPubMed 

Google Scholar * Hiroyasu Fujimori View author publications You can also search for this author inPubMed Google Scholar CORRESPONDING AUTHOR Correspondence to Kay Yakushiji. ETHICS

DECLARATIONS COMPETING INTERESTS The authors declare no competing financial interests. RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Yakushiji, K.,

Ernult, F., Imamura, H. _et al._ Enhanced spin accumulation and novel magnetotransport in nanoparticles. _Nature Mater_ 4, 57–61 (2005). https://doi.org/10.1038/nmat1278 Download citation *

Received: 21 April 2004 * Accepted: 07 September 2004 * Published: 05 December 2004 * Issue Date: January 2005 * DOI: https://doi.org/10.1038/nmat1278 SHARE THIS ARTICLE Anyone you share the

following link with will be able to read this content: Get shareable link Sorry, a shareable link is not currently available for this article. Copy to clipboard Provided by the Springer

Nature SharedIt content-sharing initiative