  Superconductivity is observed in a new nontoxic cuprate system Ga-Ba-Ca-Cu-O,
with Tc = 82K for GaBa2Ca5Cu6O14+{\delta} (Ga-1256) and Tc = 116K probably for
GaBa2Ca3Cu4O10+{\delta} (Ga-1234) or GaBa2Ca2Cu3O8+{\delta} (Ga-1223),
respectively. All compounds are fabricated by solid state reaction method under
high pressure and high temperature. Samples are characterized by resistivity,
magnetization and X-ray diffraction (XRD) measurements. The temperature
dependence of magnetization measured in both zero-field-cooled and field-cooled
processes on one sample (S1) shows two superconducting transitions at about 82K
and 113K. The estimated shielding fraction for the phase with Tc of 82K is
about 67%, while the fraction for another phase with Tc of 113K is quite small.
The XRD Rietveld refinement for S1 indicates two main phases existing in the
sample, Ga-1256 with fraction of about 58% and non-superconducting Ca0.85CuO2
with fraction of about 42%, respectively. Thus, we can conclude the
superconducting phase with transition temperature of 82K is due to Ga-1256. The
resistivity measurement also confirms the superconductivity for S1, and the
resistivity reaches zero at about 82K. The temperature dependence of
magnetization for another sample (S2) shows much higher superconducting
shielding fraction for the phase with Tc of 116K, which may be a promising
prospective for the synthesis of Ga-1234 or Ga-1223 phase.
