Publications by Mike Glazer

Confusion over the description of the quartz structure yet again


AM Glazer

Probing the intrinsic and extrinsic origins of piezoelectricity in lead zirconate titanate single crystals


N Zhang, S Gorfman, H Choe, T Vergentev, V Dyadkin, H Yokota, D Chernyshov, B Wang, AM Glazer, W Ren, Z-G Ye

Local-scale structures across the morphotropic phase boundary in PbZr1-x Ti x O3.

IUCrJ 5 (2018) 73-81

N Zhang, H Yokota, AM Glazer, DA Keen, S Gorfman, PA Thomas, W Ren, Z-G Ye

Lead zirconate titanate (PZT) is one of the most widely studied piezoelectric materials, mainly because of its 'mysterious' relationship between the so-called morphotropic phase boundary (MPB) and its strong piezoelectric coupling factor. Using results from a pair distribution function analysis, this paper examines how the complex local structure in PZT affects the long-range average structure across the MPB. A monoclinic M C type structure is discovered in PZT. A first-order transformation between the monoclinic M A and M C components in both the average and local structures explains the sudden change in piezoelectric effect around these compositions. The role of polarization rotation in the enhancement of the piezoelectric properties is discussed with respect to the composition of PZT. The structure-property relationship that is revealed by this study explains the unique properties of PZT, and may be applicable in the design of new MPB-type functional materials.

Local structures and temperature-driven polarization rotation in Zr-rich PbZr1-xTixO3


Z Wang, N Zhang, H Yokota, AM Glazer, Y Yoneda, W Ren, Z-G Ye

Monoclinic distortion, polarization rotation and piezoelectricity in the ferroelectric Na0.5Bi0.5TiO3.

IUCrJ 5 (2018) 417-427

H Choe, J Bieker, N Zhang, AM Glazer, PA Thomas, S Gorfman

The relationship between crystal structure and physical properties in the ferroelectric Na0.5Bi0.5TiO3 (NBT) has been of interest for the last two decades. Originally, the average structure was held to be of rhombohedral (R3c) symmetry with a fixed polarization direction. This has undergone a series of revisions, however, based on high-resolution X-ray diffraction, total neutron scattering, and optical and electron microscopy. The recent experimental findings suggest that the true average symmetry is monoclinic (space group Cc), which allows for a rotatable spontaneous polarization. Neither polarization rotation nor its potentially important real role in enhanced piezoelectricity is well understood. The present work describes an in situ investigation of the average monoclinic distortion in NBT by time-resolved single-crystal X-ray diffraction under external electric fields. The study presents a high-resolution inspection of the characteristic diffraction features of the monoclinic distortion - splitting of specific Bragg reflections - and their changes under a cyclic electric field. The results favour a model in which there is direct coupling between the shear monoclinic strain and the polarization rotation. This suggests that the angle of polarization rotation under a sub-coercive electric field could be 30° or more.

Relationship between the structure and optical properties of lithium tantalate at the zero-birefringence point


S Huband, DS Keeble, N Zhang, AM Glazer, A Bartasyte, PA Thomas

Crystallographic and optical study of LiNb1 - xTaxO3.

Acta crystallographica Section B, Structural science, crystal engineering and materials 73 (2017) 498-506

S Huband, DS Keeble, N Zhang, AM Glazer, A Bartasyte, PA Thomas

Powders of lithium niobate-tantalate across the full compositional range have been made and crystals grown using a lithium vanadate flux growth technique. The Li-content of a lithium tantalate crystal has been determined using the zero-birefringence temperature and Curie measurements, confirming the Li content is between that of congruent and stoichiometric crystals. X-ray diffraction measurements show the Nb/Ta displacement and octahedral tilt both decrease as the Ta content is increased. This also results in a decrease in the lattice parameters from lithium niobate to lithium tantalate. Birefringence measurements on the crystals as a function of temperature have been used to determine the point that the crystals become zero-birefringent, and by comparison with the structural studies have confirmed that it is not related to a phase transition and the structures remain polar through the zero-birefringence points.

Crystallographic and optical study of PbHfO3 crystals.

Journal of applied crystallography 50 (2017) 378-384

S Huband, AM Glazer, K Roleder, A Majchrowski, PA Thomas

The symmetry of the intermediate high-temperature phase of PbHfO3 has been determined unambiguously to be orthorhombic using a combination of high-resolution X-ray diffraction and birefringence imaging microscopy measurements of crystal plates. While lattice parameter measurements as a function of temperature in the intermediate phase are consistent with either orthorhombic or tetragonal symmetry, domain orientations observed in birefringence imaging microscopy measurements utilizing the Metripol system are only consistent with orthorhombic symmetry with the unit cell in the rhombic orientation of the pseudocubic unit cell.

X-ray white beam topography of self-organized domains in flux-grown BaTiO3 single crystals

PHYSICAL REVIEW B 94 (2016) ARTN 024110

D Walker, AM Glazer, S Gorfman, J Baruchel, P Pernot, RT Kluender, F Masiello, C DeVreugd, PA Thomas

Reconsidering the origins of Forsbergh birefringence patterns

PHYSICAL REVIEW B 94 (2016) ARTN 024109

A Schilling, A Kumar, RGP McQuaid, AM Glazer, PA Thomas, JM Gregg

Crystallography: A Very Short Introduction

Oxford University Press, 2016

AM Glazer

A. M. Glazer. A. M. Glazer CRYSTALLOGRAPHY A Very Short Introduction 1 Great Clarendon Street, Oxford, OX26DP, United Kingdom Oxford University Press Crystallography: A Very Short Introduction.

FOURIER2D and FOURIER3D: programs to demonstrate Fourier synthesis in crystallography


AM Glazer

There ain't nothing like a Dame: a commentary on Lonsdale (1947) 'Divergent beam X-ray photography of crystals'.

Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 373 (2015)

AM Glazer

Prof. Dame Kathleen Lonsdale was one of the two first female Fellows of the Royal Society, having originally been a student of that great British scientist and Nobel Laureate William Henry Bragg. She came to fame initially for her solution of the crystal structure of hexamethyl benzene, thus demonstrating that the benzene ring was flat, of considerable importance to organic chemistry, where it had been proposed before but without proof. This was at a time when the solution of crystal structures was in its infancy, and in its day this work was considered a triumph. As a rare example then of a female physicist, Lonsdale became interested in various aspects of the diffraction of X-rays, and in particular published an important paper on a form of diffraction in which a strongly divergent source was used rather than the usual highly collimated beam. The photographs thus obtained showed a series of arcs and circles, whose positions were so sensitive that they could be used to determine the quality of crystals such as diamond, and even to calculate their lattice dimensions, and hence carbon-carbon bond lengths, to hitherto extraordinary precision. Lonsdale also became known not just as a scientist but as a peace activist and an active member of the Society of Friends. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society.

Celebrating the Braggs - a Personal Account


AM Glazer

A neutron diffuse scattering study of PbZrO3 and Zr-rich PbZr1-xTixO3


N Zhang, M Pasciak, AM Glazer, J Hlinka, M Gutmann, HA Sparkes, TR Welberry, A Majchrowski, K Roleder, Y Xie, Z-G Ye

Crystal Clear The Autobiographies of Sir Lawrence and Lady Bragg

Oxford University Press, USA, 2015

AM Glazer, P Thomson

The Autobiographies of Sir Lawrence and Lady Bragg Patience Thomson. CRYSTAL CLEAR 1 CRYSTAL CLEAR The Autobiographies of Sir Lawrence and Lady.

Phase Transitions in Materials. By Brent Fultz. Cambridge University Press, 2014. Pp. 583. Price GBP 60, US$ 90. ISBN 9781107067240.

Acta crystallographica Section B, Structural science, crystal engineering and materials 71 (2015) 122-123

AM Glazer

Phase transitions and thermal-stress-induced structural changes in a ferroelectric Pb(Zr0.80Ti0.20)O3 single crystal.

Journal of physics. Condensed matter : an Institute of Physics journal 27 (2015) 025901-

J Frantti, Y Fujioka, A Puretzky, Y Xie, Z-G Ye, C Parish, AM Glazer

A single crystal of lead-zirconate-titanate, composition Pb(Zr0.80Ti0.20)O3, was studied by polarized-Raman scattering as a function of temperature. Raman spectra reveal that the local structure deviates from the average structure in both ferroelectric and paraelectric phases. We show that the crystal possesses several, inequivalent complex domain boundaries which show no sign of instability even 200 K above the ferroelectric-to-paraelectric phase transition temperature TC. Two types of boundaries are addressed. The first boundary was formed between ferroelectric domains below TC. This boundary remained stable up to the highest measurement temperatures, and stabilized the domains so that they had the same orientation after repeated heating and cooling cycles. These domains transformed normally to the cubic paraelectric phase. Another type of boundary was formed at 673 K and exhibited no signs of instability up to 923 K. The boundary formation was reversible: it formed and vanished between 573 and 673 K during heating and cooling, respectively. A model in which the crystal is divided into thin slices with different Zr/Ti ratios is proposed. The physical mechanism behind the thermal-stress-induced structural changes is related to the different thermal expansion of the slices, which forces the domain to grow similarly after each heating and cooling cycle. The results are interesting for non-volatile memory development, as it implies that the original ferroelectric state can be restored after the material has been transformed to the paraelectric phase. It also suggests that a low-symmetry structure, stable up to high temperatures, can be prepared through controlled deposition of layers with desired compositions.

Seitz symbols for crystallographic symmetry operations.

Acta crystallographica. Section A, Foundations and advances 70 (2014) 300-302

AM Glazer, MI Aroyo, A Authier

The aim of this report is to describe the Seitz notation for symmetry operations adopted by the Commission on Crystallographic Nomenclature as the standard convention for Seitz symbolism of the International Union of Crystallography. The established notation follows the existing crystallographic conventions in the descriptions of symmetry operations.

The missing boundary in the phase diagram of PbZr(1-x)TixO₃.

Nature communications 5 (2014) 5231-

N Zhang, H Yokota, AM Glazer, Z Ren, DA Keen, DS Keeble, PA Thomas, Z-G Ye

PbZr(1-x)Ti(x)O3 (PZT) is one of the most important and widely used piezoelectric materials. The study of its local and average structures is of fundamental importance in understanding the origin of its high-performance piezoelectricity. Pair distribution function analysis and Rietveld refinement have been carried out to study both the short- and long-range order in the Zr-rich rhombohedral region of the PZT phase diagram. The nature of the monoclinic phase across the Zr-rich and morphotropic phase boundary area of PZT is clarified. Evidence is found that long-range average rhombohedral and both long- and short-range monoclinic regions coexist at all compositions. In addition, a boundary between a monoclinic (M(A)) structure and another monoclinic (M(B)) structure has been found. The general advantage of a particular monoclinic distortion (M(A)) for high piezoactivity is discussed from a spatial structural model of susceptibility to stress and electric field, which is applicable across the wide field of perovskite materials science.