Vortex memory device

A superconducting memory device with a large number of memory cells in a matrix form, each memory cell comprising:

• vortex storage means constituted by a thin type-II superconductor film and for storing an Abrikosov vortex;
• write control means for generating the vortex in said vortex storage means;
• and
• vortex detecting means for detecting a polarity of the vortex stored in said vortex storage means,
• said vortex detecting means including a Josephson junction and a read control current line,
• said Josephson junction comprising a base electrode, a counter electrode and a tunnel barrier region sandwiched between said base electrode and said counter electrode,
• wherein by utilizing a fact that a shift direction of the threshold characteristics of said vortex detecting means corresponds to the polarity of said vortex stored in said vortex storage means, a flux crossing said tunnel barrier region of said Josephson junction is detected by said read control line.