Anomalous Temperature Dependence of Lower Critical Field in Ultraclean URu${}_2$Si${}_2$

R. Okazaki, M. Shimozawa, H. Shishido +7

To investigate a mysterious superconducting state of URu_2Si_2 embedded in the so-called hidden order state, the lower critical field H_{c1} is precisely determined down to 55 mK f…