Grain boundary weak link in a-b plane in MgB2 film

Artikel i vetenskaplig tidskrift, 2006

The authors have fabricated the Mg B2 bridges 850-6000 nm in width on bicrystal (111) MgO substrates with in-plane grain boundaries of the two types: 13°13° 〈110〉 and 13°13° 〈112〉. Annealing in oxygen of the films on 〈110〉 bicrystal substrates leads to a systematic decrease of critical current, a widening of the transition temperature width, and an improvement of the shape of IV curve that finally looks more like a Josephson junction. They have measured a response of such samples to the microwave radiation at 110 GHz with the voltage amplitude up to 0.5 mV.