Superconductivity: Meissner effect, Type I and II
Solid state phenomena · Physics
Study notes
Problem: A Type I superconductor has a critical temperature Tc = 7.2 K and a critical magnetic field Bc = 0.08 T at 0 K. Estimate the critical magnetic field Bc(T) at T = 5 K. Formula: Bc(T) = Bc(0) * [1 - (T/Tc)^2]. Step 1: Identify the given values. Bc(0) = 0.08 T, T = 5 K, Tc = 7.2 K. Step 2: Calculate the ratio (T/Tc). T/Tc = 5 / 7.2 ≈ 0.694. Step 3: Square the ratio. (0.694)^2 ≈ 0.482. Step 4: Subtract from 1. 1 - 0.482 = 0.518. Step 5: Multiply by Bc(0). Bc(5K) = 0.08 T * 0.518 ≈ 0.0414 T. Answer: The critical magnetic field at 5 K is approximately 0.041 T.