Electrically enhanced magnetization in highly strained BiFeO3 films

The control of magnetism via an electric field has attracted substantial attention because of potential applications in magnetoelectronics, spintronics and high-frequency devices. In this study, we demonstrate a new approach to enhance and control the magnetization of multiferroic thin film by an electric stimulus. First, to reduce the strength of the antiferromagnetic superexchange interaction in BiFeO3, we applied strain engineering to stabilize a highly strained phase. Second, the direction of the ferroelectric polarization was controlled by an electric field to enhance the Dzyaloshinskii–Moriya interaction in the highly strained BiFeO3 phase. Because of the magnetoelectric coupling in BiFeO3, a strong correlation between the modulated ferroelectricity and enhanced magnetization was observed. The tunability of this strong correlation by an electric field provides an intriguing route to control ferromagnetism in a single-phase multiferroic

Strong piezoelectricity and multiferroicity in BiFeO3–BaTiO3–NdCoO3 lead-free piezoelectric ceramics with high Curie temperature for current sensing application

Lead-free piezoelectric and multiferroic ceramics of BiFeO3-BaTiO3-NdCoO3 were synthesized by a conventional solid-state reaction method and the structural, piezoelectric, multiferroic and magnetoelectric properties of the materials were investigated. All the ceramics can be well sintered at a low sintering temperature of 980 A degrees C for 2 h. The introduction of NdCoO3 into BiFeO3-BaTiO3 induces a dramatic enhancement in the piezoelectricity, multiferroicity and magnetoelectric effect of the materials. After the addition of 1.0-3.0 mol% NdCoO3, the ceramics possess a morphotropic phase boundary of rhombohedral and orthorhombic phases and exhibit high Curie temperature (similar to 486-605 A degrees C), strong piezoelectricity, good ferroelectricity and excellent temperature stability of piezoelectricity. The greatly enhanced magnetism with M (r) = 0.4229 emu/g and M (s) = 2.7186 emu/g is obtained in the ceramic with 8.0 mol% NdCoO3, almost six times larger than that of an undoped ceramic. The ceramic with 2.0 mol% NdCoO3 shows a strong magnetoelectric effect (alpha (33) = 750 mV cm(-1) Oe(-1)). The practical application potential of the present materials has also been preliminarily demonstrated by mimicking current monitoring. Our results suggest that the present ceramics may have potential applications in advanced lead-free piezoelectric and/or multiferroic devices.Department of Electrical Engineering2016-2017 > Academic research: refereed > Publication in refereed journalbcr

First chemo-enzymatic synthesis of the ( R )-Taniguchi lactone and substrate profiles of CAMO and OTEMO, two new Baeyer– Villiger monooxygenases

This study investigates the substrate profile of cycloalkanone monooxygenase and 2-oxo-Δ3-4,5,5-trimethylcyclopentenylacetyl-coenzyme A monooxygenase, two recently discovered enzymes of the Baeyer–Villiger monooxygenase family, used as whole-cell biocatalysts. Biooxidations of a diverse set of ketones were performed on analytical scale: desymmetrization of substituted prochiral cyclobutanones and cyclohexanones, regiodivergent oxidation of terpenones and bicyclic ketones, as well as kinetic resolution of racemic cycloketones. We demonstrated the applicability of the title enzymes in the enantioselective synthesis of (R)-(−)-Taniguchi lactone, a building block for the preparation of various natural product analogs such as ent-quinine.Austrian Scientific Foundation (FWF)EU-FP7 Oxygree