Open AccessOn the incorporation of iron into hexagonal barium titanate: II. Magnetic moment, electron paramagnetic resonance (EPR) and optical transmission
Author(s) -
H. T. Langhammer,
Till Walther,
R. Böttcher,
Stefan G. Ebbinghaus
Publication year - 2020
Publication title -
journal of physics. condensed matter
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 228
eISSN - 1361-648X
pISSN - 0953-8984
DOI - 10.1088/1361-648x/ab9345
Subject(s) - paramagnetism , materials science , crystallography , nuclear magnetic resonance , physics , chemistry , condensed matter physics
Systematic measurements of the magnetic moment in dependence on temperature and magnetic field of hexagonal 6H-BaTiO 3 + 0.04 BaO + x /2 Fe 2 O 3 (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 Fe 3+ ions is detected below 200 K. The interactions between Fe 3+ 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 Fe 3+ –V O associates in the samples.