Plastic deformation of piezoelectric lanthanum-gallium tantalate crystals during cyclic mechanical actions

Kugaenko, O. M.; Uvarova, S. S.; Petrakov, V. S.; Бузанов, О. А.; Егоров, В. Н.; Sakharov, S.; Pozdnyakov, M. L.

doi:10.1134/s0036029513040071

Cited by 4 publications

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“…To fabricate a sensing element for use in pressure gages one should mechanically treat langatate crystals (cutting, polishing and grinding). How there are but scarce data on the mechanical properties of langatate crystals [8][9][10][11]. Langatate crystals have anisotropic microhardness but data of different reports scatter significantly (Table 1).…”

Section: Introductionmentioning

confidence: 99%

“…Of greatest interest is the working polar cut perpendicular to a 2 nd order axis ((101 -0) or (011 -0)) but data on the microhardness of this cut are available in only one work [11]. The optical and electrical parameters of langatate are known to depend largely on crystal growth atmosphere [12][13][14][15][16][17][18] but growth atmosphere was rarely specified in earlier works.…”

Section: Introductionmentioning

confidence: 99%

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Effect of growth conditions on the mechanical properties of lanthanum-gallium tantalate crystals

Weintraub¹,

Козлова²,

Забелина³

et al. 2020

MoEM

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The effect of growth conditions, anisotropy and polarity of specimens on the mechanical properties of lanthanum-gallium tantalate La3Ta0.5Ga5.5O14 single crystals grown in different atmospheres (argon (Ar), argon with oxygen addition (Ar+(<2%)O2 and Ar+(2%)O2) and air) was studied. The test specimens for the measurements were cut perpendicularly to a 3rd order axis (Z cuts) and in polar directions perpendicular to a 2nd order axis (Y cuts). The polarity of the Y cut specimens was tested by piezoelectric response. The brittleness was evaluated by microindentation at 3, 5, 10 and 25 g loads. The brittleness proved to show itself at a 5 g and the higher loads regardless of growth atmosphere. Therefore microhardness tests were done at loads of within 3 g. The microhardness HV of the specimens was measured with an DM 8B Affri microhardness tester by Vickers methods. The hardness H, elastic modulus E and elastic recovery coefficient R were measured with a Berkovich pyramid on a CSM Nano-Hardness Tester using the instrumented indentation (nanoindentation) method. Growth atmosphere was shown to affect the mechanical properties of lanthanum-gallium tantalate crystals: crystals grown in an oxygen-free argon atmosphere had the lowest microhardness, hardness, elastic modulus and elastic recovery coefficient. The lowest microhardness was detected in Z cut specimens regardless of growth atmosphere. The mechanical properties of polar Y cuts proved to be anisotropic: the microhardness, hardness, elastic modulus and elastic recovery coefficient of these cuts were lower for positive cuts than for negative ones regardless of growth atmosphere. Y and Z cut langatate specimens grown in argon with less than two percent oxygen exhibited strong elastic modulus and elastic recovery coefficient anisotropy.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of growth conditions on the mechanical properties of lanthanum-gallium tantalate crystals

Weintraub¹,

Козлова²,

Забелина³

et al. 2020

MoEM

View full text Add to dashboard Cite

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Bibliography

2017

Mechanics of Dislocation Fields

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A field theory of piezoelectric media containing dislocations

Taupin

Fressengeas

Ventura

et al. 2014

Journal of Applied Physics

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A field theory is proposed to extend the standard piezoelectric framework for linear elastic solids by accounting for the presence and motion of dislocation fields and assessing their impact on the piezoelectric properties. The proposed theory describes the incompatible lattice distortion and residual piezoelectric polarization fields induced by dislocation ensembles, as well as the dynamic evolution of these fields through dislocation motion driven by coupled electro-mechanical loading. It is suggested that (i) dislocation mobility may be enhanced or inhibited by the electric field, depending on the polarity of the latter, (ii) plasticity mediated by dislocation motion allows capturing long-term time-dependent properties of piezoelectric polarization. Due to the continuity of the proposed electro-mechanical framework, the stress/strain and polarization fields are smooth even in the dislocation core regions. The theory is applied to gallium nitride layers for validation. The piezoelectric polarization fields associated with bulk screw/edge dislocations are retrieved and surface potential modulations are predicted. The results are extended to dislocation loops.

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Plastic deformation of piezoelectric lanthanum-gallium tantalate crystals during cyclic mechanical actions

Cited by 4 publications

References 1 publication

Effect of growth conditions on the mechanical properties of lanthanum-gallium tantalate crystals

Effect of growth conditions on the mechanical properties of lanthanum-gallium tantalate crystals

Bibliography

A field theory of piezoelectric media containing dislocations

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