Inhomogeneous magnetic state of YFeO$_3$ thin films according to NMR spectroscopy data

Features of the magnetic state of antiferromagnetic YFeO$_3$ films thermally treated in an oxygen atmosphere and air have been studied by nuclear magnetic resonance spectroscopy. A strongly inhomogeneous distribution of local magnetic fields with characteristic scales about the interatomic distance has been revealed. The existence of two magnetically nonequivalent positions of iron ions corresponding to its different valence states has been detected in the YFeO$_3$ films under study. The relation between these nonequivalent positions of iron, as well as the degree of distortion of the crystal lattice, depends on the thermal treatment atmosphere.