Stress-Induced Cubic-to-Hexagonal Phase Transformation in Perovskite Nanothin Films

Cao, Shigu; Li, Yunsong; Wu, Hong‐Hui; Wang, Jie; Huang, Baoling; Zhang, Tong‐Yi

doi:10.1021/acs.nanolett.7b02570

Cited by 28 publications

(24 citation statements)

References 38 publications

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“…The same suggestion applies to mode 2, which is also present only in heterovalent-substituted BTO. This mode was previously associated to the presence of stress-induced hexagonal BTO phase, [29,39] but this may apply only to nanostructured or thin film BTO, and not to the present bulk case.…”

Section: Charge-compensating Defects In Heterovalent Relaxorsmentioning

confidence: 60%

Origin of Relaxor Behavior in Barium‐Titanate‐Based Lead‐Free Perovskites

Veerapandiyan

Popov

Mayer

et al. 2021

Adv Elect Materials

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perovskites, this is provided by the longrange correlation of B-site (Ti 4+ ) cation displacements. This correlation encompasses also strains up to the microscale, and is embodied by the appearance of ferroelectric domains. [3] Upon field cycling, as needed for charging-discharging the capacitor, ferroelectric domains switch in the direction of the applied field, thereby dissipating the associated elastic energy as heat. These losses are one of the main origins of the low recoverable energy density in this class of materials. [4] One often pursued strategy to increase the recoverable energy density of ceramic capacitors is thus to avoid elasticity-driven losses by disembodying electric charge from elastic strain through the disruption of the long-range correlation of Ti 4+ displacements. [2] When BTO is substituted at the perovskite B-site, in fact, the correlation of TiOTi chains is broken; [5] consequently, ferroelectric domains cease to permeate the whole lattice and are rather confined to nanoscale polar regions, whose size, correlation and distribution depends on substituent type and concentration. [6] The absence of longrange strain correlation limits the losses associated with elastic energy and slims down the polarization-electric field (P-E) hysteresis loop, thereby increasing the recoverable energy density, [2] provided that the achievable polarization at the maximum

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Section: Charge-compensating Defects In Heterovalent Relaxorsmentioning

confidence: 60%

Origin of Relaxor Behavior in Barium‐Titanate‐Based Lead‐Free Perovskites

Veerapandiyan

Popov

Mayer

et al. 2021

Adv Elect Materials

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show abstract

“…A number of studies have noted a profound effect of internal pressure in controlling the phase transitions [27][28][29]. In addition, hydrostatic pressure is well-known to govern the phase transition in a number of compounds [30][31][32]. However, there is no previous indication of hydrostatic pressure driven polytypism in Nowotny-Juza phases, but a priori one should consider hydrostatic pressure also as a potential driving force of polytypism in Nowotony-Juza phases.…”

Section: Introductionmentioning

confidence: 99%

Polytypism at its best: improved thermoelectric performance in Li based Nowotony-Juza phases

Chopra¹,

Zeeshan²,

Pandey³

et al. 2018

Preprint

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In principle thermoelectricity is a viable route of converting waste heat into electricity, but the commercialization of the technology is limited by its present efficiency. In quest of improved materials, utilizing an ab initio approach, we report polytypism induced improved thermoelectric performance in Li based Nowotny-Juza phases LiZnX (X = N, P, As, Sb, and Bi). In addition to LiZnSb, we find that cubic LiZnBi is energetically more favorable than the hitherto explored hexagonal phase whereas the hexagonal polytypes of cubic LiZnP, and LiZnAs are likely to be stabilized by pressure -hydrostatic pressure can be aided by internal pressure to facilitate the phase transition. We find a pronounced impact of the polytypism on thermoelectric properties. We determine conservative estimates of the figure of merit and find that while power factor and figure of merit values are improved in hexagonal phases, the values in cubic phases are still excellent. The ZT values of cubic and hexagonal LiZnSb at 700 K are 1.27 and 1.95, respectively. Other promising ZT values at 700 K are 1.96 and 1.49 of hexagonal LiZnP and LiZnAs, respectively, for n-type doping. Overall, our findings proffers that the Nowotny-Juza phases are a new potential class of thermoelectric materials.Usage: Secondary publications and information retrieval purposes.

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“…Ferroelectrics with switchable polarization, excellent dielectric, piezoelectric, and pyroelectric properties have a wide range of applications in memories, capacitors, actuators, sensors, and electrocaloric cooling devices. [1][2][3][4][5][6][7][8][9][10][11][12] As a typical ferroelectric material, barium titanate (BaTiO 3 ) possesses a rich variety of phase transitions. 13 Above its Curie temperature (T C~1 20°C), the BaTiO 3 single crystal is paraelectric phase with cubic symmetry.…”

Section: Introductionmentioning

confidence: 99%

A thermodynamic potential for barium zirconate titanate solid solutions

et al. 2018

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Barium zirconate titanate [Ba(Zr x Ti 1−x)O 3 ] solid solutions are promising lead-free ferroelectric materials that have received substantial interest. Thermodynamic analysis based on phenomenological Landau-Devonshire theory is a powerful method for theoretical investigation of ferroelectric materials, but cannot be applied to Ba(Zr x Ti 1−x)O 3 because there is no thermodynamic potential. In this paper, a thermodynamic potential for Ba(Zr x Ti 1−x)O 3 (0 ≤ x ≤ 0.3) solid solutions is constructed, and then a thermodynamic analysis carried out. The results accurately reproduce known phase structures and their transition temperatures, with good agreement with experimentally measured polarization, dielectric, and piezoelectric constants. It is found that Ba(Zr x Ti 1−x) O 3 solid solutions at room temperature have three phase boundaries, including a tetragonal-orthorhombic phase boundary at x = 0.013, an orthorhombic-rhombohedral phase boundary at x = 0.0798, and a rhombohedral-paraelectric phase boundary at x = 0.2135. The results also indicate that the chemical composition-induced ferroelectric-paraelectric phase boundary has superior electromechanical properties, suggesting a new way to enhance electromechanical coupling in Ba(Zr x Ti 1−x)O 3 solid solutions.

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Stress-Induced Cubic-to-Hexagonal Phase Transformation in Perovskite Nanothin Films

Cited by 28 publications

References 38 publications

Origin of Relaxor Behavior in Barium‐Titanate‐Based Lead‐Free Perovskites

Origin of Relaxor Behavior in Barium‐Titanate‐Based Lead‐Free Perovskites

Polytypism at its best: improved thermoelectric performance in Li based Nowotony-Juza phases

A thermodynamic potential for barium zirconate titanate solid solutions

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