Superfluid density and volume fraction of static magnetism in stripe-stabilized La1.85-yEuySr0.15CuO4

Muon spin relaxation measurements have been performed in the optimally doped La1.85-yEuySr0.15CuO4, where the static spin stripes are stabilized by the rare-earth doping. Zero-field measurements indicate that the volume fraction V-Cu of static magnetism increases with increasing Eu concentration, while the ordered moment size remains constant. Transverse-field measurements show that n(s)/m(*) (superconducting carrier density/effective mass) at T-->0 is proportional to the non-magnetic volume fraction (1 - V-Cu). These results indicate that superconductivity and static stripe magnetism occur in different spatial regions, exclusively, suggestive of microscopic phase separation. (C) 2002 Elsevier Science B.V. All rights reserved.