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Epitaxial strain can induce the formation of morphotropic phase boundary in lead free ferroelectrics like bismuth ferrite, thereby enabling the coexistence of tetragonal and rhombohedral phases in the same film. The relative ratio of these phases is governed by the film thickness and theoretical studies suggest that there exists a monoclinic distortion of both the tetragonal as well as the rhombohedral unit cells due to imposed epitaxial strain. In this work we show that optical second harmonic generation can distinguish the tetragonal-like phase from the rhombohedral-like phase and enable detection of monoclinic distortion in only a pure tetragonal-like phase. [ABSTRACT FROM AUTHOR]

The CoFe2O4-BaTiO3 core-shell (CFO@BTO) nanocomposites have been synthesized, and a particular volume fraction of 15% CoFe2O4–85% BaTiO3 has been studied for its magnetic, ferroelectric, and magnetoelectric properties. The optimization of synthesis conditions showed that a temperature of at least 800 °C is required to obtain pure phase BaTiO3, whereas for the tetragonality to be visible in the x-ray diffraction (XRD) pattern, BaTiO3 needed to be sintered to at least 1050 °C. Even though the CFO@BTO composite began to react at the interface at 1050 °C and a small amount of the secondary phase was observed in the XRD pattern, the ferroelectric and magnetic properties were found to be not affected. Upon treating the living epithelial cells with either CFO@BTO or BTO nanoparticles, no toxicity was observed for up to 7 days. Together, these results establish the potential for the use of CFO@BTO nanoparticles in biomedical applications. [ABSTRACT FROM AUTHOR]

By employing temperature (T)-dependent soft x-ray magnetic circular dichroism (XMCD) in the Fe and Cr 2p absorption edges, the electronic structures of Li 0.5 FeCr 1.5 O4 spinel ferrite, which exhibits magnetization compensation, have been investigated. This work provides evidence that (i) both Fe and Cr ions are trivalent, (ii) most of Fe 3 + ions occupy the A (Td) sites, while Cr 3 + ions occupy the B (Oh) sites, (iii) the magnetic moments of Fe and Cr ions are coupled antiferromagnetically, and (iv) they are reversed at ∼ 255 K. The sum-rule analysis of Fe and Cr 2p XMCD spectra reveals that the orbital magnetic moments of Fe and Cr ions in Li 0.5 FeCr 1.5 O4 are much larger than those of metallic Fe and Cr, implying the large spin–orbit coupling and the non-fully occupied t 2 g orbitals of Fe 3 + and Cr 3 + ions. Based on these findings, we have provided a comprehensive model for the electronic and spin configurations of Fe and Cr ions in (Fe)A[ Li 0.5 Cr 1.5 ]BO4. [ABSTRACT FROM AUTHOR]