Longitudinal relaxation measurements in the ferromagnetic phase of the superconducting state of Eu-based pnictides

We aim to perform zero and longitudinal field muon spin relaxation measurements in order to investigate anomalous spin dynamics effects observed in EuFe2(As1-xPx)2 with x=0.20 when ferromagnetism and superconductivity coexist at low temperature. In this system the Curie temperature is lower than the superconducting critical temperature, hence it offers an optimal playground to explore the interplay between the coexisting orders. The interplay between superconductivity and magnetism remains one of the main enigmas in Physics. The ISIS muon facility is the most suitable to measure slow muon spin relaxations of the longitudinal component expected for this compound and will be complementary to other techniques with different time windows, such as microwave and ac magnetization measurements.

本研究旨在开展零场与纵向场μ子自旋弛豫（muon spin relaxation）测量，以探究x=0.20的EuFe₂(As₁₋ₓPₓ)₂在低温条件下铁磁性与超导性共存时所观测到的反常自旋动力学效应。该体系中居里温度低于超导临界温度，因此为探究共存有序相之间的相互作用提供了绝佳的研究平台。超导与磁学之间的相互作用仍是物理学领域的核心未解之谜之一。ISISμ子源（ISIS muon facility）是开展该化合物预期的纵向分量慢μ子自旋弛豫测量的最优实验装置，且可与微波、交流磁化率测量等具备不同时间窗口的其他实验技术形成互补。