Abstract
Glass-ceramics with cubic BaTiO3 as a major and hexagonal BaTi1-xFexO3-δ as a second phase were prepared by crystallization at 560 °C in a glass with the composition 20.1Na2O/23TiO2/23.1BaO/3Al2O3/7.6B2O3/17.4SiO2/5.8Fe2O3. X-ray photoelectron spectroscopy revealed presence of Ti4+ and Fe3+ ions in tetrahedral and octahedral coordination. Ba2+ occurs in different environments depending on the thermal history of the samples. The numbers of bridging and non-bridging oxygens vary with the crystallization time. Electron paramagnetic resonance spectroscopy showed four types of Fe3+ ions that are non-uniformly distributed in the samples: Fe3+ ions in magnetic domains, isolated Fe3+ in a rhombic crystal field, magnetically coupled Fe3+ ions in BaTiO3 and Fe3+ ions located in a crystalline phase. The ratio between the described types of Fe3+ ions depends on the annealing time. Mössbauer spectroscopy detected Fe3+ tetrahedral and octahedral coordinated in the glass. Fe3+ was incorporated in distorted octahedral and pentahedral coordination in the Ti4+ sites of hexagonal BaTiO3 crystals, the electroneutrality being preserved by the occurrence of oxygen vacancies. Vibrating sample magnetometer measurements were used to determine ferromagnetic properties in samples crystallized for times ≥ 3 h. Maximum magnetization of 0.8 emu/g and a coercive force of 25 Oe were determined for the sample crystallized for 3 h at 560 °C.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
