Exploring the magnetic, optical and dielectric properties of Cr- doped hematite (α-Fe(2−x)CrxO3): A comprehensive study

Abstract

Magnetic, dielectric, and optical properties of Cr-doped hematite (α-Fe2O3) i.e. α-Fe(2−x)CrxO3 (x = 0.00, 0.03, 0.06, 0.10, 0.20) have been investigated in the present work. The nanospheres with excellent mono dispersity have been synthesized successfully by facile hydrothermal treatment at 160 °C. Rhombohedral structure with space group R3C for all the nanostructures have been revealed from X-ray diffraction patterns and the spectrum is compatible with the Raman active phonon modes. Raman spectra in response to the effects of doping indicated microscopic structural disarray. The α-Fe(2−x)CrxO3 nanostructures have exhibited enhanced ferromagnetic characteristics comparable to undoped hematite(α-Fe2O3). The potential of coercivity in the α-Fe(2−x)CrxO3 system has not been fully excavated, which restricts its practical application to a certain extent. With the increase of Cr3+ doping level in α-Fe2O3 and decrease in the particle size. we have successfully attained the highest coercivity values as it increases from 1481.98–5273.75 Oe, with good signatures of remnant magnetization indicating the capability of Cr3+ doping in boosting the magnetic properties of α-Fe2O3 for magnetic applications such as magnet tapes, magnetic data storage devices, and permanent magnets. The domain state of magnetization and interaction fields were comprehensively investigated by first-order reversal curve analysis (FORCs). With Cr doped α-Fe2O3, we observed an enhanced dielectric constant with the highest dielectric constant of 25.10 in Fe1.85Cr0.15O3. and extremely low dielectric losses. Due to their incredibly low dielectric losses, these nanostructures are ideally suited for implementation in high-frequency microwave device applications. The absorption edges have been reinforced to higher wavelengths, in addition to enhanced visible absorption in the visible region and reduced optical bandgaps. The lowest bandgap 1.66 eV is observed in α-Fe1.85Cr0.15O3 due to additional levels introduced between valence and conduction bands. This study suggests that the magnetic, dielectric, and optical properties of hydrothermally prepared α-Fe2O3 systems can be largely tailored with Cr content making them suitable candidates for spintronics, optoelectronic and magneto-optical devices.