Photoinduced Electron Spin Resonance Phenomenon in α‐Cr₂O₃ Nanospheres

Abstract

The photoinduced phenomenon in -Cr 2 O 3 nanoscaled 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 in -Cr 2 O 3 under 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 temperature N . Such a photoinduced ESR phenomenon disappears in a reproducible way in the paramagnetic insulating state which occurs above N of crystalline -Cr 2 O 3 . In the antiferromagnetic phase, that is, below N , the shift of the low field absorption could be attributed to the interaction of the light with specific Cr 3+ ions located in strongly distorted sites correlated to strong ligand-field effect.

Single-phase α-Cr2O3 nanoparticles’ green synthesis using Callistemon viminalis’ red flower extract

“…In view of the potential applications of the synthesized pure Eskolaite α-Cr 2 O 3 , it was shown that they do exhibit superior supercapacitance response in a composite form with graphene (12). Likewise, they display a tunable photo-induced magnetism as demonstrated recently (14,16) and hence the possibility to engineer novel photo-tunable magnetic devices.…”

“…Because of its high chemical stability, α-Cr 2 O 3based catalysts are also of importance for the chemical industry in the preparation of several important commodity chemicals and have also been investigated for their potential as Li cathodes (4)(5)(6)(7)(8)(9)(10). As a result of its high refractive index, it is also finds use in cermets designed for low and medium temperature-selective solar absorbers (11)(12)(13)(14)(15)(16).…”

Physiochemical properties and novel biological applications of Callistemon viminalis‐mediated α‐Cr2O3 nanoparticles

“…Due to high chemical stability and catalytic potential, Cr 2 O 3 has gained substantial importance in the chemical industry . It has been used for low‐ and medium‐temperature selective solar absorber due to its high refractive index . Anticancer and antibacterial properties of α‐Cr 2 O 3 are also reported …”

Concomitant Magnetic Memory Effect in CrO2–Cr2O3 Core–Shell Nanorods: Implications for Thermal Memory Devices

“…The resonant absorption of an AF material usually requires frequency in the THz region because of the large exchange field of antiferromagnetic interaction confirming the AF nature of Cr 2 O 3 NRs. At 300 K, a highly intense and distorted ESR spectrum was obtained from CrO 2 NRs, whereas a single line ESR spectrum in the PM field region is the characteristic of Cr 2 O 3 NRs Figure e shows the temperature dependences of the inverse of the doubly integrated area (1/DIA) of ESR spectra from 33 to 250 K. We can see that the FM correlations strengthen with cooling for all samples.…”