Two Phase Collective Modes in Josephson Vortex Lattice in Intrinsic Josephson Junction Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$

Abstract

Josephson plasma excitations in the high $T_c$ superconductor Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$ have been investigated in a wide microwave frequency region (9.8 -- 75 GHz), in particular, in magnetic field applied parallel to the $ab$ plane of the single crystal. In sharp contrast to the case for magnetic fields parallel to the c axis or tilted from the $ab$ plane, it was found that there are two kinds of resonance modes, which are split in energy and possess two distinctly different magnetic field dependences. One always lies higher in energy than the other and has a shallow minimum at about 0.8 kOe, then increases linearly with magnetic field. On the other hand, another mode begins to appear only in a magnetic field (from a few kOe and higher) and has a weakly decreasing tendency with increasing magnetic field. By comparing with a recent theoretical model the higher energy mode can naturally be attributed to the Josephson plasma resonance mode propagating along the primitive reciprocal lattice vector of the Josephson vortex lattice, whereas the lower frequency mode is assigned to the novel phase collective mode of the Josephson vortex lattice, which has never been observed before.

11 pages and 10 figures

References in corpus (8)

• Crossing lattices, vortex chains, and angular dependence of melting line in layered superconductors
• Plasma resonance and remaining Josephson coupling in the ``decoupled vortex liquid phase'' in layered superconductors
• Possible critical point in phase diagrams of interlayer Josephson-vortex systems in high-Tc superconductors
• Dynamic structure selection and instabilities of driven Josephson lattice in high-temperature superconductors
• Josephson Coupling, Phase Correlations, and Josephson Plasma Resonance in Vortex Liquid Phase
• New Josephson Plasma Modes in Underdoped YBa2Cu3O6.6 Induced by Parallel Magnetic Field
• Josephson Plasma Excitation and Vortex Oscillation Mode in Josephson Vortes State
• Josephson Plasma Resonance in Solid and Glass Phases of Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$

Cited by in corpus (5)

• Scaling behavior of the crossover to short-stack regimes of Josephson vortex lattices in Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$ stacks
• Electrodynamics of Josephson vortex lattice in high-temperature superconductors
• In-plane current-voltage characteristics and oscillatory Josephson-vortex flow resistance in La-free Bi${}_{2+x}$Sr${}_{2-x}$CuO${}_{6+\delta }$ single crystals in high magnetic fields
• In-plane field-induced vortex liquid correlations in underdoped Bi_2Sr_2CaCu_2O_8+δ
• Mapping the dynamic interactions between vortex species in highly anisotropic superconductors