Magnetic-field dependence of the low-temperature specific heat of La2-xSrxCuO4

Recently, possible evidence from the low-temperature specific heat (LTSH) for the lines of nodes in the superconducting order parameter of cuprate superconductors has attracted much attention and is still debated. To clarify this issue and to cover the studies in different carrier doping regimes, we have measured LTSH of La2-xSrxCuO4 (s = 0.10, 0.16, and 0.22) both in zero and applied magnetic fields. In all doping regimes, it is found that the increase in the Linear-T coefficient gamma is proportional to H-1/2, consistent with d-wave supercon ductivity. The data shows clear evidence for an alpha T-2 term at zero magnetic field in LTSH of La1.78Sr0.22CuO4. Furthermore, our results are compared with the recently proposed scaling theory.