Synthesis, dielectric, and magneto – dielectric properties of carbon quantum dots/ZnFe₂O₄ hybrid nanocomposite

Abstract

Carbon quantum dots doped ZnFe₂O₄ Spinel Ferrite, that is, CQD-ZSF hybrid nanocomposite was thrivingly synthesised exploiting sol-gel based synthesis technique. Structural assessment supports Fd-3m space group with cubic spinel structure with mean size of 10.33 nm as obtained from Scherrer formula. Raman spectra confirmed the existence of CQD in ZSF. The samples contained a variety of vibration bands, according to the FT-IR analysis. The dielectric permittivity (ε) and tangent losses (tan δ) was conducted with frequency from 100 Hz to 1 MHz range at different temperatures ranging from 300 to 773 K. It was found that ε as well as tan δ receded monotonously with extending frequency. This information reveals a space or interfacial dipolar relaxation phenomenon. The electrical properties and the ion hopping dynamics were probed with the assistance of an AC-electrical conductivity (σ_ac) analysis. Frequency-dependent σ_ac heeded Jonscher’s law of power. The advent of arcs semicircular by nature in cole-cole plot indicates cloud of electronic process occurring within sample. At 300 K, by applying an external magnetic field varying till 1.5 Tesla magnetic field, the magneto-dielectric effects of the sample were measured by obtaining ε and tan δ versus frequency values displaying negative ML% (magneto-loss) and MD% (magneto-dielectric) coupling of −32.57% and −58.13%, respectively.

Keywords:

• Carbon quantum dots doped ZnFe₂O₄ spinel ferrite [CQD-ZSF] hybrid nanocomposite
• sol-gel
• dielectric properties
• magnetodielectric properties

Acknowledgment

Rutam Biswal thanks DST, New Delhi, for DST Inspire Fellowship. sAlso gratitude to DST, New Delhi, for financial support to the Centre of Materials Sciences under FIST Programme (Grant No. SR/FST/PSI-216/2016).

Disclosure statement

No potential conflict of interest was reported by the authors.