Localized GHz frequency electrodynamic behavior of an optimally-doped Ba(Fe1−xCo )2As2 epitaxial film

Abstract

Localized high frequency (several GHz) electrodynamic properties of a high quality epitaxial, single-crystal Iron-Pnicitde Ba(Fe 1−x Co x ) 2 As 2 thin film near optimal doping (x=0.08) are measured under a localized and strong RF magnetic field, created by a near-field microwave microscope. Two reflection electrodynamic measurements, including linear and the third harmonic responses, are performed to understand the electromagnetic properties of Ba(Fe 1−x Co x ) 2 As 2 . Our measurement results show that Ba(Fe 1−x Co x ) 2 As 2 has have a wide superconducting transition width and may have a multi-gap nature. In addition, based on the 1/T 2 dependence of the third harmonics signal at lower temperature, Ba(Fe 1−x Co x ) 2 As 2 shows the possibility of nodal behavior.

Dynamic Microwave Impedance of Dc-Biased Josephson Fluxonic Diode in the Presence of Magnetic Field and RF Drive

“…The response of Josephson junctions (JJs) to rf excitation has been the subject of an enormous amount of research over the last decades. Shapiro steps [1], I-V characteristics [2], microwave impedance [3] and chaos [4,5] are several cases in this field which have been extensively studied both theoretically and experimentally for these family of superconducting devices similar to single crystals [6], weak links [7,8], SIS [9] and long Josephson Junctions (LJJs) [10]. The microwave impedance of these intrinsic and extrinsic devices has shown a remarkable nonlinear dependence to the rf drive which can be described in terms of Josephson-like response.…”

Особенности нелинейного СВЧ-отклика многозонных сверхпроводников на основе ферроселенида натрия-калия (Na-=SUB=-0.3-=/SUB=-K-=SUB=-0.7-=/SUB=-)-=SUB=-x-=/SUB=-Fe-=SUB=-2-y-=/SUB=-Se-=SUB=-2-=/SUB=-

“…Для решения актуальных задач требуется создание новых методов исследования сверхпроводящего состояния. Одним из таких перспективных методов является метод ближнепольной СВЧ-микроскопии [13][14][15][16]. Преимущество данной методики заключается в возможности локальной и бесконтактной диагностики наличия нескольких энергетических щелей и необычной симметрии параметра порядка в сверхпроводнике.…”