The photoinduced phenomenon inα-Cr2O3nanoscaled spherical particles was investigated in the temperature range of 150 up to 315 K. An X-band electron-spin resonance spectrometry was employed to probe the magnetic behavior inα-Cr2O3under an IR illumination in the nanosecond regime. The photoinduced effect on both low and high field ESR signals appears above 280 K and is remarkably enhanced just below Néel temperatureTN. Such a photoinduced ESR phenomenon disappears in a reproducible way in the paramagnetic insulating state which occurs aboveTNof crystallineα-Cr2O3. In the antiferromagnetic phase, that is, belowTN, the shift of the low field absorption could be attributed to the interaction of the light with specific Cr3+ions located in strongly distorted sites correlated to strong ligand-field effect.
Photoinduced Electron Spin Resonance Phenomenon inα-Cr2O3Nanospheres