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Tunneling Via Individual Electronic States in Ferromagnetic Nanoparticles

S. Gueron·Mandar M. Deshmukh·E. B. Myers·D. C. Ralph
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Abstract

We measure electron tunneling via discrete energy levels in ferromagnetic cobalt particles less than 4 nm in diameter, using non-magnetic electrodes. Due to magnetic anisotropy, the energy of each tunneling resonance shifts as an applied magnetic field rotates the particle's magnetic moment. We see both spin-increasing and decreasing tunneling transitions, but we do not observe the spin degeneracy at small magnetic fields seen previously in non-magnetic materials. The tunneling spectrum is denser than predicted for independent electrons, possibly due to spin-wave excitations.

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S. Gueron, Mandar M. Deshmukh, E. B. Myers, D. C. Ralph. 1999-09-27. Tunneling Via Individual Electronic States in Ferromagnetic Nanoparticles. https://doi.org/10.1103/physrevlett.83.4148

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