The Senn Group is growing – meet our new group members! Fernando joins us from Argentina on a 2 year fellowship funded by the Marie Skłodowska Curie Action and the Institute of Advanced Study of the University of Warwick, Anna is starting her PhD in the group on a studentship part funded by the ISIS Neutron and Muon SourceRead more
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Mark S. Senn and Nicolas C. Bristowe, Acta Crystallographica Section A: Foundations and Advances, 2018, Volume A74, pages 308-321 A group-theoretical approach is used to enumerate the possible couplings between magnetism and ferroelectric polarization in the parent Pm-3m perovskite structure. It is shown that third-order magnetoelectric coupling terms must always involve magnetic ordering at theRead more
Hanna L. B. Boström, Mark S. Senn and Andrew L. Goodwin, Nature Communications (2018) 9:2380 The central goal of crystal engineering is to develop precise control over material function via rational design of structure. A particularly successful realisation of this paradigm is the example of hybrid improper ferroelectricity in layered perovskite materials, where cation vacanciesRead more
Improper ferroelectric polarization in a perovskite driven by intersite charge transfer and ordering
Wei-Tin Chen, Chin-Wei Wang, Hung-Cheng Wu, Fang-Cheng Chou, Hung-Duen Yang, Arkadiy Simonov, and Mark S. Senn, Phys. Rev. B 97, 144102 (2018) There has recently been renewed interest in improper ferroelectricity due to the discovery of a “hybrid” mechanism by which two nonpolar lattice modes couple to a third polar mode. Here, the authorsRead more
At least one fully funded Royal Society PhD studentship for 4 years (UK fees and stipend) is available within the senngroup. The project will be in the field of multiferroic materials within the broader area of research encompassed by materials chemistry, solid state science and physical crystallography. The start date of the PhD studentship will be October 2018, and the project will be conducted at the UniversityRead more
Chris has headed off this month for a 7 month long industrial placement at BOSCH in Boston, Massachusetts, USA. He will be putting his PhD research on negative thermal expansion in layered Perovskites on hold during this period and applying his computational modeling skills to new challenges in an industrial lead R&D environment. Good luck Chris, and we lookRead more
Chris Ablitt, Sarah Craddock, Mark S. Senn, Arash A. Mostofi & Nicholas C. Bristowe, npj Computational Materials 3, Article number: 44 (2017) doi:10.1038/s41524-017-0040-0 Why is it that ABO3 perovskites generally do not exhibit negative thermal expansion (NTE) over a wide temperature range, whereas layered perovskites of the same chemical family often do? It isRead more
D. G. Porter, M. S. Senn, D. D. Khalyavin, A. Cortese, N. Waterfield-Price, P. G. Radaelli, P. Manuel, H.-C. zur-Loye, C. Mazzoli, and A. Bombardi The magnetic ground state of Sr3ARuO6 , with A=(Li,Na) , is studied using neutron diffraction, resonant x-ray scattering, and laboratory characterization measurements of high-quality crystals. Combining these results allows usRead more
Ronghuan Zhang, Mark S. Senn, and Michael A. Hayward, Chem. Mater., DOI: 10.1021/acs.chemmater.6b03931 The cooperative tilting distortions of n = 2 Ruddlesden–Popper oxides can be utilized to break the inversion symmetry of the host lattice and induce ferroelectric behavior. Unfortunately the desired a–a–c+/a–a–c+ structural deformation is only stabilized in phases with extremely small structuralRead more
M. S. Senn, D. A. Keen, T. C. A. Lucas, J. A. Hriljac, and A. L. Goodwin, Phys. Rev. Lett. 116 (2016), 207602. By using a symmetry motivated basis to evaluate local distortions against pair distribution function data (PDF), we show without prior bias, that the off-centre Ti displacements in the archetypal ferroelectric BaTiO3 are zone centred and rhombohedral-like in natureRead more