Negative muon spin rotation and relaxation on superconducting MgB2

Paper in proceeding, 2023

The internal nuclear magnetic field in a superconducting MgB2 powder sample was studied with a μ- SR technique. Although the past μ +SR study on MgB2 reported the appearance of a dynamic behavior even below Tc due to μ + diffusion, μ- SR shows a static behavior in the whole temperature range measured, as expected. The ZF-μ- SR spectra do not suggest any appearance of additional magnetic field below Tc within the experimental accuracy. Considering the small asymmetry of the μ- SR signal, it is a challenge to detect the appearance of an internal magnetic field below Tc caused by the time reversal symmetry breaking.