Influence of erbium doping on the structural, magnetic and optical properties of hematite (α-Fe2O3) nanorods. (October 2022)

• Record Type: Journal Article
• Authors: Popov, Nina; Ristić, Mira; Kuncser, Victor; Zadro, Krešo; Velinov, Nikolay; Badica, Petre; Alexandru-Dinu, Andrei; Iacob, Nicusor; Kratofil Krehula, Ljerka; Musić, Svetozar; Krehula, Stjepko
• Is Part Of: Journal of physics and chemistry of solids. Volume 169(2022)
• Publication Date: 2022-10
• Subjects: Hematite -- Erbium -- Nanorods -- Mössbauer spectroscopy -- Morin transition; Solids -- Periodicals; Solides -- Périodiques; Solids; Periodicals; 530.41
• DOI: 10.1016/j.jpcs.2022.110857
• Languages: English
• ISSNs: 0022-3697

Abstract

Abstract: Pure and Er-doped hematite (α-Fe2 O3 ) nanorods were prepared by a two-step method involving hydrothermal synthesis and calcination of pure and Er-doped goethite (α-FeOOH) nanorods. Substitution of Fe 3+ by Er 3+ in the crystal structure of hematite caused morpho-structural changes such as expansion of the unit cell and gradual shortening and rounding of hematite nanorods towards formation of nanoellipsoids. These changes induced modification of magnetic and optical properties suggesting the possibility of a systematic control of physical properties via rare earth substitution. A decrease in the hyperfine magnetic field, coercive field and Morin transition temperature, as well as an increase of the magnetic susceptibility and a narrowing of the optical band gap were observed by substitution. Intimate mechanisms related to the formation of more and more defect-like hematite phases with decreased temperatures for the transition to the low temperature antiferromagnetic phase at increased doping level were evidenced via temperature dependent Mössbauer spectroscopy. Highlights: Fairly uniform Er-doped hematite nanorods and nanoelipsoids were prepared. The particle shape depended on the molar fraction of erbium. Temperature of the Morin transition decreased by Er doping. Magnetic susceptibility increased by Er doping due to uncompensated spins. The optical band gap slightly narrowed by Er doping.