  Very recent report [1] on observation of superconductivity in Bi4O4S3 could
potentially reignite the search for superconductivity in a broad range of
layered sulphides. We report here synthesis of Bi4O4S3 at 5000C by vacuum
encapsulation technique and basic characterizations. Detailed structural,
magnetization, and electrical transport results are reported. Bi4O4S3 is
contaminated by small amounts of Bi2S3 and Bi impurities. The majority phase is
tetragonal I4/mmm space group with lattice parameters a = 3.9697(2){\AA}, c =
41.3520(1){\AA}. Both AC and DC magnetization measurements confirmed that
Bi4O4S3 is a bulk superconductor with superconducting transition temperature
(Tc) of 4.4K. Isothermal magnetization (MH) measurements indicated closed loops
with clear signatures of flux pinning and irreversible behavior. The lower
critical field (Hc1) at 2K, of the new superconductor is found to be ~39 Oe.
The magneto-transport R(T, H) measurements showed a resistive broadening and
decrease in Tc (R=0) to lower temperatures with increasing magnetic field. The
extrapolated upper critical field Hc2(0) is ~ 310kOe with a corresponding
Ginzburg-Landau coherence length of ~100{\AA} . In the normal state the {\rho}
~ T2 is not indicated. Our magnetization and electrical transport measurements
substantiate the appearance of bulk superconductivity in as synthesized
Bi4O4S3. On the other hand same temperature heat treated Bi is not
superconducting, thus excluding possibility of impurity driven
superconductivity in the newly discovered Bi4O4S3 superconductor.
