Probing magnetism and superconductivity of high-Tc systems with positive muons

Recent results from our μSR experiments on high-Tc systems are presented. We describe studies of static magnetic order in hole-doped and electron-doped systems, correlations between Tc and ns/m* (carrier density / effective mass) in hole-doped superconducting cuprates, the temperature dependence of the penetration depth in c-axis oriented sintered ceramic of Y Ba2Cu3O7, as well as the detection of flux pinning phenomena by μSR.