Novel photoactive magnetic semiconductor nanocomposites with potential magneto-optical properties

Abstract

A novel magnetic semiconductor nanocomposite based on functionalized magnetite nanoparticles (MNPs) embedded in a matrix of bismuth ferrate compound (BFO) was obtained in a single step for the first time using the microwave-assisted hydrothermal synthesis. The synthesis method allows obtaining multiferroic BFO small particles and MNPs-BFO nanocomposites with optical activity in the near-infrared region (1.6 eV) due to d-d charge transfer transitions on Fe(III) ion orbitals. The functionalized MNPs exhibit strong superparamagnetic behavior with blocking temperature T B near room temperature and high saturation magnetization of M S = 59 emu/g, attributed to ferrimagnetic nano-monodomains with critical size. Meanwhile, the synthesized BFO shows an unusual superparamagnetic behavior with T B = 20 K and an interesting magnetic transition from the blocked superparamagnetic state to quantum superparamagnetic state at a critical temperature T c = 11 K, attributed to ferromagnetic very small, critical size nano-monodomains. As result, the MNPs-BFO nanocomposite shows a superparamagnetic behavior at room temperature which, in close connection with its optical properties, makes it an excellent candidate for infrared magneto-optical applications.

Engineered magnetic oxides nanoparticles as efficient sorbents for wastewater remediation: a review

“…After around 45 min, ≈ 98% of methylene orange was removed in the presence of the optimal core-shell nanosized catalyst. Juan et al (García et al 2021) studied a photoactive semiconductor nanomaterial (magnetite nanoparticles embedded in a bismuth ferrate matrix using a microwave-assisted hydrothermal approach. The as-fabricated bismuth ferrate samples display a 2 nd absorption wavelength 535 nm equivalent to an energy value of ~ 2.3 eV that matched the stated E g for bismuth ferrate bulk systems.…”