Abstract
We report measurements of the temperature dependence of the surface impedance in superconducting BaFe1.93Ni0.07As2 crystals using the radiofrequency reflection technique in the 5<T<30K temperature range. An LC resonant circuit with a phase sensitive detection was used at 92MHz. A measurement assembly with point contacts was used at 30MHz. The recent discovery of iron based arsenide superconductors BaFe2-xNixAs2 has attracted much interest. For a Ni doping level of 7% the superconducting phase transition is found around 20K. The temperature dependence of the superconducting penetration depth was determined.
Highlights
The recent discovery of iron based arsenide superconductors BaFe2-xNixAs2 has attracted much interest [1,2,3]
We report measurements of the temperature dependence of the surface impedance in superconducting BaFe1.93Ni0.07As2 crystals using the radiofrequency reflection technique in the 5
It is found that V0 drops precipitously as the temperature is lowered through TC in the BaFe1.93Ni0.07As2 crystal Fig1
Summary
The recent discovery of iron based arsenide superconductors BaFe2-xNixAs2 has attracted much interest [1,2,3]. The imaginary part is determined by the response of the superconducting carriers and characterized the non dissipating energy stored in the superconducting surface layer λ which is the magnetic penetration depth. After the sample passes from the superconducting to the normal sate, the magnetic field penetrates into the sample a much larger distance equal to the normal skin depth δ. For our samples, this distance is of the order of 70 μm at 100 MHz. The second probe for the superconducting carriers is the use of ultrasonic measurements. In a superconductor well below the superconducting transition TC attenuation of sound waves are markedly lower than in a normal metal
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
