On the incorporation of iron into hexagonal barium titanate: I. electron paramagnetic resonance (EPR) study

Böttcher, R.; Langhammer, H. T.; Kücker, S; Eisenschmidt, C.; Ebbinghaus, Stefan G.

doi:10.1088/1361-648x/aadea8

Cited by 5 publications

(20 citation statements)

References 42 publications

(66 reference statements)

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“…Ti(2) -V O(1) to be most stable, in which the oxygen vacancy is located in the O(1) plane connecting the face-sharing oxygen octahedra. In contrast, our current EPR data exclude the formation of this defect, in accordance with our finding in the case of Fe-doped hexagonal BaTiO 3 [29,30].…”

Section: Introductionsupporting

confidence: 92%

“…Dominant in this spectrum are the fine structure lines of the isolated Fe 3? ions, which are present in our crystals as an impurity of the starting materials. These lines are very sharp because of the very low Fe concentration of B 70 ppm [29]. The spectrum of the Fe-V O associate [29] was also detectable but lies outside the magnetic field range shown.…”

Section: Q-band Epr Investigations On Single Crystalsmentioning

confidence: 83%

“…These lines are very sharp because of the very low Fe concentration of B 70 ppm [29]. The spectrum of the Fe-V O associate [29] was also detectable but lies outside the magnetic field range shown. The presence of further paramagnetic impurities (Mn, Cr) leads to the resonances near the central fine structure line of the isolated Fe 3? ions.…”

Section: Q-band Epr Investigations On Single Crystalsmentioning

confidence: 83%

“…and a vacancy in the surrounding oxygen octahedron (see Fig. 5 in [29]). The symmetry of the angular dependence can easily be understood by the six possible positions of the associate in each Ti(1)O 6 or Ti(2)O 6 unit.…”

Section: Q-band Epr Investigations On Single Crystalsmentioning

confidence: 99%

“…For B jj c, all six associate positions are equivalent, whereas for B jj b = [0 1 0] h four positions cause a resonance field of 10.96 kG and the remaining two positions a resonance field of 9.94 kG, which is illustrated in Fig. 9 of [29] by a sketch of the TiO 6 unit in relation to the rotation axis [2 1 0] h . This scenario of a Ni 3?…”

Section: Q-band Epr Investigations On Single Crystalsmentioning

confidence: 99%

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On the incorporation of nickel into hexagonal barium titanate: magnetic properties and electron paramagnetic resonance (EPR)

et al. 2020

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Systematic measurements of the magnetic moment of hexagonal 6H-BaTiO3 + 0.04 BaO + x NiO (0.005 ≤ x ≤ 0.02) ceramics were performed to study the influence of Ni ions on the magnetic properties. By temperature-dependent measurements of the paramagnetic susceptibility at 90 kOe, the Ni2+ ion was identified as the majority defect in air-sintered Ni-doped hexagonal barium titanate. Q-band EPR investigations of a 2.0 mol% Ni-doped single crystal revealed three different Ni centers located at Ti sites: first, Ni3+ ions at Ti sites in intact oxygen octahedra, second, Ni3+ associated with an oxygen vacancy and third, the presence of Ni2+ centers leading to a forbidden transition. The Ni3+—VO associate characterized by a vacancy in the face-sharing oxygen plane of the oxygen octahedra can be ruled out. The crystal field parameters of the Ni2+ defect were estimated by a combined fitting of the paramagnetic susceptibility and the EPR fine structure parameter D to $$B_{0}^{4}$$ B 0 4 ≈ −17,300 cm−1, $$\left| {B_{0}^{2} } \right|$$ B 0 2 ≈ 2500 cm−1 and $$B_{3}^{4}$$ B 3 4 ≈ 19,000 cm−1.

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Section: Introductionsupporting

confidence: 92%

Section: Q-band Epr Investigations On Single Crystalsmentioning

confidence: 83%

Section: Q-band Epr Investigations On Single Crystalsmentioning

confidence: 83%

Section: Q-band Epr Investigations On Single Crystalsmentioning

confidence: 99%

Section: Q-band Epr Investigations On Single Crystalsmentioning

confidence: 99%

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On the incorporation of nickel into hexagonal barium titanate: magnetic properties and electron paramagnetic resonance (EPR)

et al. 2020

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On the incorporation of iron into hexagonal barium titanate: II. Magnetic moment, electron paramagnetic resonance (EPR) and optical transmission

Langhammer

Walther

Böttcher

et al. 2020

J. Phys.: Condens. Matter

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Systematic measurements of the magnetic moment in dependence on temperature and magnetic field of hexagonal 6H-BaTiO3 + 0.04 BaO + x/2 Fe2O3 (0.005 ⩽ x ⩽ 0.05) ceramics were performed to study the influence of Fe ions on the magnetic properties. While the samples show Curie–Weiss paramagnetism for Fe concentrations ⩽1.0 mol%, antiferromagnetic interactions become manifest for 2.0 and 5.0 mol% iron. With increasing Fe content the antiferromagnetic interaction, which is assumed to be caused by a superexchange mechanism F e T i ( 1 ) 3 + − O O ( 2 ) 2 − − F e T i ( 2 ) 3 + , becomes stronger. At external magnetic fields smaller than 1 T a further, ferromagnetic interaction between Fe3+ ions is detected below 200 K. The interactions between Fe3+ ions in the samples with 2.0 and 5.0 mol% iron are also manifest in the EPR spectra by numerous lines with low intensity. Q-band EPR investigations of 5.0 mol% Fe doped single crystals confirm the existence of only one type of Fe3+–VO associates in the samples.

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Defect properties of vanadium doped barium titanate ceramics

Böttcher

Langhammer

Walther

et al. 2019

Mater. Res. Express

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X-ray diffraction (XRD) patterns, electron probe microanalysis (EPMA), electron paramagnetic resonance (EPR) powder spectra (9 and 34 GHz) and the magnetic susceptibility of BaTiO3 + 0.04 BaO + 0.01 V2O5 ceramics were studied to investigate the valence states of V ions and their solubility in the BaTiO3 lattice. In samples sintered at 1400 °C in air, only about 0.1 mol% V is incorporated in the BaTiO3 lattice being in V4+ and V5+ valence state, respectively. 95% of the nominal V dopant content occurs in the secondary phase Ba3(V/Ti)2O8. All BaTiO3 samples investigated are in tetragonal phase at room temperature. In the as-sintered samples V4+ is detected at temperatures T < 20 K by its hyperfine structure (HFS) octet due to the nuclear spin 7/2 of 51V. Samples post-annealed in H2/Ar atmosphere at 1200 °C exhibit a further HFS octet occurring at T > 25 K and vanishing at T > 250 K, which is caused by V2+ ions. This spectrum is characterized by a simultaneous HFS and fine structure splitting constituted by allowed and forbidden transitions. Both V4+ and V2+ ions are incorporated at Ti4+ sites of the BaTiO3 lattice.

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On the incorporation of iron into hexagonal barium titanate: I. electron paramagnetic resonance (EPR) study

Cited by 5 publications

References 42 publications

On the incorporation of nickel into hexagonal barium titanate: magnetic properties and electron paramagnetic resonance (EPR)

On the incorporation of nickel into hexagonal barium titanate: magnetic properties and electron paramagnetic resonance (EPR)

On the incorporation of iron into hexagonal barium titanate: II. Magnetic moment, electron paramagnetic resonance (EPR) and optical transmission

Defect properties of vanadium doped barium titanate ceramics

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