Current Fluctuations in Ferromagnetic Tunnel Junctions
B.R. Bułkaa, J. Martineka, G. Michałeka and J. Barnaśb
a Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland
bDepartment of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland
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Current shot noise in a double junction consisting of a small metallic grain connected to two ferromagnetic electrodes is analysed in the limit of sequential tunneling. We show that, apart from charge fluctuations, there are strong spin fluctuations. We also show that two distinct relaxation processes can be distinguished in the frequency dependent current noise: one in a low frequency range and corresponding to spin fluctuations and another one in a high frequency range corresponding to charge fluctuations.
DOI: 10.12693/APhysPolA.97.423
PACS numbers: 75.70.Pa, 73.50.Td, 73.23.Hk, 73.40.Gk