Upper critical field and thermopower studies in Ni substituted Li2Pd3B superconductor

The upper critical field (Hc2) 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 (Tc) exhibits a linear decrease with an increase in the magnetic field above 0.5 T. Hc2(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.