Muon spin rotation study of field-induced magnetism in heavily overdoped La2-xSrxCuO4

In the huge volume of research on the cuprates, there is very little that investigates the properties of the highly overdoped area of the phase diagram, where superconductivity disappears with increased carrier concentration. In the spirit of further exploring this region, we have performed the first known muSR measurements of heavily overdoped single-crystalline La2-xSrxCuO4. We discovered an anomalous field-induced broadening of the internal magnetic field distribution. The broadening is linear in applied field and has a Curie-Weiss temperature dependence. Furthermore, the effect increases with doping above x=0.12 and is maximal at our highest doping (x=0.3). Possible relaxation mechanisms are discussed.