The effect of La substitution on the strength of spontaneous magnetic fields in Sr2RuO4

It is predicted that spontaneous electrical currents appear around crystalline defects, domain walls and surfaces in superconductors with broken time-reversal symmetry. However, the experimental evidence in favour of this prediction is mixed. Here, we propose to investigate the effect of inhomogeneities created by La doping in Sr2RuO4 using zero-field µSR measurements. The anticipated results will allow an understanding of the relation of the spontaneous field strength with defect density and the size of the superconducting order parameter.