Observation of Magnetic Ordering in SuperconductingLa2−xSrxCuO4by Muon Spin Rotation

Abstract

Muon spin rotation experiments performed on superconducting ${\mathrm{La}}_{2-x}{\mathrm{Sr}}_x\mathrm{Cu}{\mathrm{O}}_4$ samples clearly show that internal magnetic fields coexist at low temperatures ($T<\mathrm{}2\mathrm{}$ K) with superconductivity for $x\le 0.15$. The magnetic fields in the superconducting state are an order of magnitude smaller than the corresponding fields in undoped ${\mathrm{La}}_2$Cu${\mathrm{O}}_4$. The data are discussed in the context of a magnetic pairing mechanism in high-$T_c$ superconductors.