Magnetic penetration depth in electron-doped cuprates - evidence for gap nodes
arXiv:cond-mat/9912001 · doi:10.1016/S0921-4534(00)00945-X
Abstract
The in-plane penetration depth λ(T) is measured in electron-doped single crystals Nd1.85Ce0.15CuO4-x (NCCO) and Pr1.85Ce0.15CuO4-x (PCCO) using a 11 MHz LC resonator. In NCCO, λ(T) exhibits a minimum at 3.8 K and a pronounced upturn down to 0.4 K due to the paramagnetic contribution of Nd3+ ions. The London penetration depth contribution is linear in T. The paramagnetic contribution is absent in PCCO, where λ(T)~T^2 at low temperatures. Our results indicate the presence of nodes in the superconducting gap, i.e., non s-wave symmetry of the order parameter in electron-doped cuprates.
2 pages Acrobat-3 optimized PDF. To be presented at M2S-HTSC-VI