The interlayer penetration depth in layered superconductors may be determin
ed from scanning Superconducting QUantum Interference Device (SQUID) micros
cope images of interlayer Josephson vortices. We compare our findings at 4
K for single crystals of the organic superconductor kappa-(BEDT-TTF)(2)Cu(N
CS)(2) and three near-optimally doped cuprate superconductors: La2-xSrxCuO4
, (Hg,Cu)Ba2CuO4+delta, and Tl2Ba2CuO6+delta.