6533b851fe1ef96bd12a9a3c
RESEARCH PRODUCT
Frequency dependence of the microwave surface resistance of MgB2 by coaxial cavity resonator
M. Li VigniP. CamardaA. Agliolo GallittoA. Figini AlbisettiGiovanni Giunchisubject
Materials scienceMgB2 superconductorSuperconducting cavity resonatorSettore FIS/01 - Fisica SperimentaleMagnesium diborideEnergy Engineering and Power TechnologySuperconducting cavity resonator; Magnesium diboride; Microwave surface resistanceCondensed Matter PhysicsElectronic Optical and Magnetic MaterialsConductorResonatorchemistry.chemical_compoundCoaxial cavity resonatorchemistryCoaxial cavityMicrowave surface resistanceExcited stateQuasiparticleMagnesium diborideElectrical and Electronic EngineeringAtomic physicsMicrowaveSheet resistancedescription
Abstract We report on the microwave (mw) properties of a cylindrical MgB2 rod prepared by the reactive liquid Mg infiltration technology. The MgB2 rod, 94.3 mm long, is used as inner conductor of a coaxial cavity having a Cu tube as external conductor. By analyzing the resonance curves of the cavity in the different resonant modes and at different temperatures, we have determined the temperature dependence of the mw surface resistance, R s , of the MgB2 material, at fixed frequencies, and the frequency dependence of R s , at fixed temperatures. Our results show that the R s ( f ) curves follow a f n law, where n decreases on increasing the temperature, starting from n ≈ 2 , at T = 4.2 K , down to n ≈ 0.7 at T ⩾ T c . The double-gap nature of MgB2 manifests itself in the presence of a wide low-T tail in the R s ( T ) curves, which can be ascribed to the quasiparticles thermally excited through the π gap even at relatively low temperatures.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2014-01-01 | Physica C: Superconductivity and its Applications |