Mesoscopic resistance fluctuations in cobalt nanoparticles.
We present measurements of mesoscopic resistance fluctuations in cobalt nanoparticles and study how the fluctuations with bias voltage, bias fingerprints, respond to magnetization-reversal processes. Bias fingerprints rearrange when domains are nucleated or annihilated. The domain wall causes an electron wave function-phase shift of approximately equal to 5pi. The phase shift is not caused by the Aharonov-Bohm effect; we explain how it arises from the mistracking effect, where electron spins lag in orientation with respect to the moments inside the domain wall. Dephasing time in Co at 0.03 K is short, tau phi approximately 1 ps, which we attribute to the strong magnetocrystalline anisotropy.
Wei
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Georgia Institute of Technology, Atlanta, GA 30332, USA.
Liu
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Zhang
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Davidović
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