Static magnetic order in electron-superconductor related compounds

Using the technique of muon spin relaxation, we have shown that the parent compounds Ln2CuO4-y where [Ln=(Nd, SmorPr)] of the new electron-superconductors exhibit static magnetic order below 300 K. No static magnetic order with any appreciable moment was observed above 4 K in superconducting samples of Nd2-χCeχCuO4−y for χ > .155. Measurements on a single crystal of Nd2CuO4−y show magnetic order with a sharp onset at 250 K, followed by a number of changes in the ordered spin direction at T ∼ 65 K and T ∼ 33 K.