Figure 3.

Thickness dependence of upper critical field and critical temperature. (a) Temperature dependence of critical field $H_{c2\parallel ab}$ and $H_{c2\parallel c}$ for 5.5, 7, 10 and 14 nm samples. The T_c values are normalized by the zero field transition temperature T_c0. The H_c2 values are normalized by the paramagnetic Pauli limit μ₀H_p = 1.84T_c0. (b) The thickness dependence of the superconducting transition temperature (top) and the in-plane upper critical field $H_{c2\parallel ab}$ (red circle) as well as the Pauli limit H_p (black circle) (bottom) at base temperature T = 20 mK. The solid lines are drawn for guidance to eye.