Upper critical field and thermopower studies in Ni substituted Li2Pd3B superconductor

The upper critical field ( H c 2 ) and thermopower ( S ) of samples belonging to the series Li2(Pd1−xNix)3B with x = 0.0 to 0.2 have been studied. The superconducting transition temperature ( T c ) exhibits a linear decrease with an increase in the magnetic field above 0.5 T. H c 2 ( T = 0 ) estimated by linear extrapolation was found to decrease with increasing Ni concentration. The thermopower of samples with x = 0  and  x = 0.2 shows linear temperature dependence in the 77–300 K range, with the negative value of S ( T ) indicating electrons as the charge carrier in this temperature range. However, S ( T ) of the pristine sample exhibits a positive value below 40 K, indicating the possibility of holes being the predominant charge carriers at low temperatures in Li2Pd3B.