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

The antiferromagnetic manganite Pr0.5Sr0.5-MnO3 was investigated at low tem perature by means of magnetometry and Mn-55 NMR. A field-induced transition to a ferromagnetic state is detected by magnetization measurements at a th reshold field of a few tesla. NMR shows that the ferromagnetic phase develo ps from zero field by the nucleation of microscopic ferromagnetic domains, consisting of an inhomogeneous mixture of tilted and fully aligned parts. A t the threshold the NMR spectrum changes discontinuously into that of a hom ogeneous, fully aligned, ferromagnetic state, suggesting a percolative orig in for the ferromagnetic transition.