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.

预测表明，在时间反演对称性（time-reversal symmetry）破缺的超导体中，晶体缺陷、畴壁及表面周围会出现自发电流。然而，支持这一预测的实验证据并不一致。本文提出采用零场μ子自旋弛豫（μSR）测量，研究Sr2RuO4中La掺杂产生的不均匀性效应。预期结果将有助于理解自发场强与缺陷密度及超导序参量（superconducting order parameter）大小之间的关系。