  We report on the fabrication and electrical transport properties of
superconducting quantum interference devices (SQUIDs) made from a
(Bi_{1-x}Sb_x)_2Se_3 topological insulator (TI) nanoribbon (NR) connected with
Pb0.5In0.5 superconducting electrodes. Below the transition temperature of the
superconducting Pb0.5In0.5 electrodes, periodic oscillations of the critical
current are observed in the TI NR SQUID under a magnetic field applied
perpendicular to the plane owing to flux quantization. Also the output voltage
modulates as a function of the external magnetic field. Moreover, the SQUID the
SQUID shows a voltage modulation envelope, which is considered to represent the
Fraunhofer-like patterns of each single junction. These properties of the TI NR
SQUID would provide a useful method to explore Majorana fermions.

Superconductivity;Mesoscale and Nanoscale Physics