T. A. Bird, A. Herlihy and Mark S. Senn, J. Appl. Cryst. (2021). 54. A novel symmetry-adapted pair distribution function analysis (SAPA) method for extracting information on local distortions from pair distribution function data is introduced. The implementation of SAPA is demonstrated in the TOPAS-Academic software using the freely available online software ISODISTORT, and scripts for converting theRead more
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Gabriel Clarke, Chris Ablitt, John Daniels, Stefano Checchia and Mark S. Senn. J. Appl. Cryst. (2021) 54. Improper ferroelectric materials are increasingly under investigation for their potential to expand the catalogue of functional ferroelectrics and couple with properties such as ferromagnetism. This work presents the results of an in situ synchrotron X-ray diffraction experiment performedRead more
Fernando Pomiro, Chris Ablitt, Nicholas C. Bristowe, Arash A. Mostofi, Choongjae Won, Sang-Wook Cheong, and Mark S. Senn.Phys. Rev. B 102, 014101. Hybrid improper ferroelectrics (HIFs) have been studied intensively over the past few years to gain an understanding of their temperature-induced phase transitions and ferroelectric switching pathways. Here we report a switching from aRead more
Tobias Bird, Jessica Woodland-Scott, Lei Hu, Michael Wharmby, Jun Chen, Andrew Goodwin, Mark Senn, Phys. Rev. B 101(2020), 064306. We use a symmetry-motivated approach to analysing X-ray pair distribution functions to study the mechanism of negative thermal expansion in two ReO3-like compounds; ScF3 and CaZrF6. Both average and local structure suggest that it is the flexibilityRead more
Chris Ablitt, Harriet McCay, Sarah Craddock, Lauren Cooper, Emily Reynolds, Arash A. Mostofi, Nicholas C. Bristowe, Claire A. Murray, and Mark S. Senn. Chem. Mater. 2020, 32, 1, 605-610. By tuning the tolerance factor, t, of the Ruddlesden–Popper oxide Ca2MnO4 through isovalent substitutions, we show that the uniaxial coefficient of linear thermal expansion (CLTE) ofRead more
S. R. Popuri, R. Decourt, J. A. McNulty, M. Pollet, A. D. Fortes, F. D. Morrison, M. S. Senn, and J. W. G. Bos. J. Phys. Chem. C 10.1021/acs.jpcc.8b10520 The phonon–glass electron crystal concept is one of the key guiding principles for the development of efficient thermoelectric materials. Here, we confirm that SrTiO3 becomes aRead more
Wei-Tin Chen, Chris Ablitt, Nicholas C. Bristowe, Arash A. Mostofi, Takashi Saito, Yuichi Shimakawaf and Mark S. Senn . Chem. Commun., 2019, Advance Article 10.1039/C8CC09614G We report the high pressure synthesis of a layered perovskite Ca2GeO4 which is found to have the Ruddlesden–Popper structure with I41/acd symmetry. Consonant with our recent predictions [Ablitt et al.,Read more
Ablitt C, Mostofi AA, Bristowe NC and Senn MS (2018) Control of Uniaxial Negative Thermal Expansion in Layered Perovskites by Tuning Layer Thickness. Front. Chem. 6:455. doi: 10.3389/fchem.2018.00455 Uniaxial negative thermal expansion (NTE) is known to occur in low $n$ members of the An+1$BnO3n+1 Ruddlesden–Popper layered perovskite series with a frozen rotation of BO_6 octahedra about the layering axis. PreviousRead more
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