Field-induced segregation of ferromagnetic nanodomains in Pr0.5Sr0.5MnO3 detected by 55Mn NMR

The antiferromagnetic manganite Pr0.5Sr0.5-MnO3 was investigated at low temperature by means of magnetometry and Mn-55 NMR. A field-induced transition to a ferromagnetic state is detected by magnetization measurements at a threshold field of a few tesla. NMR shows that the ferromagnetic phase develops from zero field by the nucleation of microscopic ferromagnetic domains, consisting of an inhomogeneous mixture of tilted and fully aligned parts. At the threshold the NMR spectrum changes discontinuously into that of a homogeneous, fully aligned, ferromagnetic state, suggesting a percolative origin for the ferromagnetic transition.