## Abstract

A proximity effect in an s-wave superconductor/ferromagnet (SC/F) junction is theoretically studied using the second order perturbation theory for the tunneling Hamiltonian and Green's function method. We calculate a pair amplitude induced by the proximity effect in a weak ferromagnetic metal (FM) and a half-metal (HM). In the SC/FM junction, it is found that a spin-singlet pair amplitude (Ψ_{s}) and spin-triplet pair amplitude (Ψ_{t}) are induced in FM and both amplitudes depend on the frequency in the Matsubara representation. Ψ_{s} is an even function and Ψ_{t} is an odd function with respect to the Matsubara frequency (ω_{n}). In the SC/HM junction, we examine the proximity effects by taking account of magnon excitations in HM. It is found that the triplet-pair correlation is induced in HM. The induced pair amplitude in HM shows a damped oscillation as a function of the position and contains the terms of even and odd functions of ω_{n} as in the case of the SC/FM junction. We discuss that in our tunneling model the pair amplitude of even function of ω_{n} only contributes to a Josephson current.

Original language | English |
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Pages (from-to) | 3257-3260 |

Number of pages | 4 |

Journal | Journal of Physics and Chemistry of Solids |

Volume | 69 |

Issue number | 12 |

DOIs | |

Publication status | Published - 2008 Dec |

## Keywords

- A. Superconductor

## ASJC Scopus subject areas

- Chemistry(all)
- Materials Science(all)
- Condensed Matter Physics