TY - JOUR
T1 - Spin injection in ferromagnet/superconductor/ferromagnet tunnel junctions
AU - Takahashi, S.
AU - Imamura, H.
AU - Maekawa, S.
N1 - Funding Information:
The suppression of the superconducting gap A by spin injection is detected by measuring the critical current J¢. According to the Ginzburg-Landau theory, J¢ is proportional to A 3, because J¢ cx A2v~ and vc ~ A, v~ being the critical velocity [12]. Figure 4 shows the cube of the normalized gap, (A/Ao)3, and thus the normalized critical current, (Jc / Jc 0), as a function of the injection current for gi = 1/2 (R1 = R2) and Fs << 1. In the case that FM1 and FM2 are the same FM (top panel), the critical current J¢ in the AF alignment is strongly reduced and vanishes at a small Iinj, whereas there is no suppression of J¢ in the F alignment. In the case of different FMs (middle panel), J¢ decreases with increase of Iinj in both alignments but in a different way. If one of FMs is replaced by a normal metal (N), we have a heterostructure junction FM1/SC/N, which corresponds to the case of P2 = 0 in the bottom panel, where we added the curves at T/Tc = 0.95 and T/Tc = 0.99 for comparison with experimental data. The calculated result for P2 = 0 explains the suppression of the critical current by spin injection observed in the heterostructure junctions consisting of a high-To SC and a ferromagnetic manganite with P ,--100 % [9]. This work is supported by a Grant-in-Aid for Scientific Research Priority Area for Ministry of Education, Science and Culture of Japan, CREST, and NEDO.
PY - 2000
Y1 - 2000
N2 - We theoretically study the spin-dependent transport in a ferromagnet/superconductor/ferromagnet double barrier tunnel junction. The spin-polarized tunneling currents create spin and charge imbalance in a superconductor. Nonequilibrium effects are dominated by spin imbalance, causing an unusual spin transport and suppression of superconductivity depending on whether the magnetizations of the electrodes are parallel or antiparallel. Recent experimental results on the critical current suppression by spin injection are discussed.
AB - We theoretically study the spin-dependent transport in a ferromagnet/superconductor/ferromagnet double barrier tunnel junction. The spin-polarized tunneling currents create spin and charge imbalance in a superconductor. Nonequilibrium effects are dominated by spin imbalance, causing an unusual spin transport and suppression of superconductivity depending on whether the magnetizations of the electrodes are parallel or antiparallel. Recent experimental results on the critical current suppression by spin injection are discussed.
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U2 - 10.1016/S0921-4534(00)01317-4
DO - 10.1016/S0921-4534(00)01317-4
M3 - Article
AN - SCOPUS:0343832954
VL - 341-348
SP - 1515
EP - 1518
JO - Physica C: Superconductivity and its Applications
JF - Physica C: Superconductivity and its Applications
SN - 0921-4534
IS - PART 2
ER -