Microwave absorption studies of MgB2 superconductor

Microwave absorption studies have been carried out on MgB₂ superconductor using a standard X-band EPR spectrometer. The modulated low-field microwave absorption signals recorded for polycrystalline (grain size ～ 10 µm) samples suggested the absence of weak-link character. The field dependent direct microwave absorption has been found to obey a ?H dependence with two different slopes, which indicated a transition from strongly pinned lattice to flux flow regime.