The effects of non-stoichiometric lattice structure and secondary phase α-Fe2O3 on modifying the magnetic, electrical, and magneto-electric properties of Eu doped BaFe12O19 hexaferrite

Gara Kishor; R. N. Bhowmik; P. D. Babu

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arXiv · 2610.13499

The effects of non-stoichiometric lattice structure and secondary phase α-Fe2O3 on modifying the magnetic, electrical, and magneto-electric properties of Eu doped BaFe12O19 hexaferrite

Gara Kishor·R. N. Bhowmik·P. D. Babu

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Abstract

The Ba-atoms in BaFe12O19 were substituted by Eu-atoms to prepare the material of composition Ba1-xEuyFe12O19. The Eu atoms occupied at the sites of Fe atoms. The atomic ratio of Eu/Ba were varied from 0 to 0.33 to control the secondary phase (hematite) and M-type hexaferrite. Raman spectra provided complimentary support for a systematic increase of the hematite phase on increasing the Eu/Ba ratio. X-ray photoelectron spectroscopy informed the presence of oxygen deficiency and surface defects, and charge state of Ba and Fe/Eu ions close to +2 and +3, respectively. The material showed direct optical transitions with band gap in the range of 2.25-3.09 eV. The increase of Eu/Ba ratio systematically increased the saturation magnetization from 84.44 emu g-1 to 57.68 emu g-1 at 3 K and 67.09 emu g-1 to 43.42 emu g-1 at 300 K, along with remarkable enhancement of the coercivity (914- 3656 Oe at 3 K and 1996-4862 Oe at 300 K). Electrical conductivity increased from 10-11-10-10 Sm-1 at 30 K to 10-5 -10-4 Sm-1 at 300 K. The electrical conductivity analysis reveals the Efros-Shklovsky-type variable-range hopping mechanism at the low-temperature region, whereas the Mott variable range hopping mechanism is applicable near to room temperature. The analysis of current-voltage characteristics provided electrode to sample interfacial barrier height of 0.27-0.74 eV. The material exhibited novel magneto-electronic properties (bi-stable electronic switching and its transformation in the temperature scale, magnetoresistance and magnetoelectric coupling) which are highly useful for spintronic devices. This work demonstrates that controlled Eu/Ba atomic ratio in the stoichiometric and non-stoichiometric lattice structure could be an effective strategy to widely tune the magnetic, optical and magneto-electronic properties in M-type Ba hexaferrite material.

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Gara Kishor, R. N. Bhowmik, P. D. Babu. 2026-10-09. The effects of non-stoichiometric lattice structure and secondary phase α-Fe2O3 on modifying the magnetic, electrical, and magneto-electric properties of Eu doped BaFe12O19 hexaferrite. https://arxiv.org/abs/2610.13499

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