Tuesday, June 18, 2013

1306.3652 (S. Hikino et al.)

Zero-Field Fiske Resonance Coupled with Spin-waves in Ferromagnetic
Josephson Junctions

S. Hikino, M. Mori, S. Maekawa
AC Josephson current in a Josephson junction with voltage bias is spatially modulated by an ex- ternal magnetic field, and induces an electromagnetic (EM) field inside the junction. The current- voltage (I-V) curve exhibits peaks due to the resonance between the EM field and the spatially modulated AC Josephson current. This is called Fiske resonance. Such a spatially modulated Josephson current can be also induced by a non-uniform insulating barrier and the Fiske resonance appears without external magnetic field. This is called zero-field Fiske resonance (ZFFR). In this pa- per, we theoretically study the ZFFR coupled with spin-waves in a superconductor/ferromagnetic insulator/superconductor junction (ferromagnetic Josephson junction) with a non-uniform ferro- magnetic insulating barrier. The resonant mode coupled with spin-waves can be induced without external magnetic field. We find that the I-V curve shows resonant peaks associated with composite excitations of spin-waves and the EM field in the junction. The voltage at the resonance is obtained as a function of the normal modes of EM field. We show several current-density dependences of the ZFFRs coupled with spin-waves.
View original: http://arxiv.org/abs/1306.3652

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