We measure the magnetic-field dependence of the $c$-axis resistivity, ${\rho }_c\left(H\right)$, in a series of ${\mathrm{Bi}}_2{\mathrm{Sr}}_{2-x}{\mathrm{La}}_x\mathrm{Cu}{\mathrm{O}}_{6+\mathrm{\delta }}$ (BSLCO) single crystals for a wide range of doping using pulsed magnetic fields up to 58 T. The behavior of ${\rho }_c\left(H\right)$ is examined in light of the recent determination of the upper critical field $H_{c2}$ for this material using Nernst effect measurements. We find that the peak in ${\rho }_c\left(H\right)$ shows up at a field $H_p$ that is much lower than $H_{c2}$ and there is no discernable feature in ${\rho }_c\left(H\right)$ at $H_{c2}$. Intriguingly, $H_p$ shows a doping dependence similar to that of $T_c$, and there is an approximate relation $k_B{T}_c\simeq \frac{1}{2}g{\mu }_B{H}_p$. Moreover, we show that the data for the lowest-$T_c$ sample can be used to estimate the pseudogap closing field $H_{pg}$, but the method to estimate $H_{pg}$ proposed by Shibauchi et al.[Phys. Rev. Lett. 86, 5763 (2001)] must be modified to apply to the BSLCO system.

• Received 3 August 2004

DOI:https://doi.org/10.1103/PhysRevB.70.224521