An addition to the TikZ Circuit library. Currently it provides an ideal Josephson junction (cross) and a Josephson junction with an intrinsic capacitance (boxed cross).
The jjtikz files should be accesible to LaTex. The simplest solution is to put them in to your working directory.
A more civilized approach is to use the TEXMF folder. You can utilize a provided Makefile. On a Unix-like system with LiveTex type
make install
This installs the library to ~/texmf/tex/latex/
documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{circuits.ee.IEC,circuits.superconducting}
\begin{document}
\begin{tikzpicture}[circuit ee IEC]
\draw (0,0) to[JJ cap] (1,0) to[JJ] (2,0);
\end{tikzpicture}
\end{document}