Journal of the American Ceramic Society最新文献

{"title":"The effect of pressure on the aluminoborosilicate glass optical basicity","authors":"Gabin Haryouli,&nbsp;Sami Soudani,&nbsp;Stéphane Grolleau,&nbsp;Michael Paris,&nbsp;Yann Morizet","doi":"10.1111/jace.20359","DOIUrl":"https://doi.org/10.1111/jace.20359","url":null,"abstract":"<p>The glass optical basicity (Λ) is an adequate way of representing a glass composition that has been successfully applied for glasses made under ambient pressure conditions. However, we do not know if the proposed calculation based on the glass structure and the proposed measurement involving the determination of glass refractive index can apply to glasses made under high-pressure conditions. We studied several aluminoborosilicate glass compositions synthesized under high-pressure conditions up to 3 GPa and 1250°C. Recovered glasses were characterized to determine the refractive index (n_D) and the density (ρ). The glass structure was determined using ¹¹B and ²⁷Al nuclear magnetic resonance. Increasing pressure up to 3 GPa increases n_D and ρ for the studied glasses. Change in the glass structure is consistent with previous studies showing an increase in Al coordination, especially for Ca-bearing glass composition; and an increase in the proportion of BO₄ species. The glass optical basicity decreases with increasing pressure. From the structural changes, Λ decreases by ∼2% from ambient to 1 GPa in pressure for the investigated glass compositions.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143530493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Boosting the melting point record to 4431 K: Simulated with machine learning potential at SCAN accuracy","authors":"Fu-Zhi Dai,&nbsp;Yifen Xu,&nbsp;Jidong Hu,&nbsp;Shipeng Zhu,&nbsp;Xin-Fu Gu","doi":"10.1111/jace.20356","DOIUrl":"https://doi.org/10.1111/jace.20356","url":null,"abstract":"<p>Carbides or carbonitrides in the Hf-Ta-C-N system are believed to exhibit the highest melting point, attracting significant interest for both scientific and engineering means. In this study, we developed a machine learning potential model for Hf-Ta-C-N carbonitrides at Strongly Constrained and Appropriately Normed (SCAN) semi-local density functional accuracy. In addition, we proposed a novel critical equilibrium method for simulating melting points. Utilizing these two advancements, we successfully simulated solidus and liquidus lines in phase diagrams of HfC₁₋<i>_x</i> and TaC₁₋<i>_x</i>, demonstrating excellent agreement with experimental results. We then discovered new compounds with even higher melting points by employing Bayesian global optimization. The compound with the highest melting point found is Hf_0.956Ta_0.044C_0.600N_0.338, which has a melting point of 4431 K, surpassing the experimental record by approximately 150 K. We conducted an in-depth thermodynamic analysis in the HfC–HfN pseudo-binary system and found that the addition of N has a dual effect: on the one hand, it increases the enthalpy change due to melting (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>Δ</mi>\u0000 <mi>H</mi>\u0000 <mo>↑</mo>\u0000 </mrow>\u0000 <annotation>$Delta H uparrow $</annotation>\u0000 </semantics></math>) with a maximum value at ∼15 at% N in the anion site; on the other hand, it reduces the entropy of the liquid phase and increases the entropy of the solid phase (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>Δ</mi>\u0000 <mi>S</mi>\u0000 <mo>↓</mo>\u0000 </mrow>\u0000 <annotation>$Delta S downarrow $</annotation>\u0000 </semantics></math>). This results in a maximum melting point at a specific N content. Furthermore, we discussed the effects of N alloying on thermal expansion and mechanical properties, which are invaluable for the ongoing development of carbonitrides. This research not only advances our understanding of Hf-Ta-C-N carbonitrides but also provides a promising framework for future materials research and the development of materials with exceptional properties.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143530152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated experimental and thermodynamic modeling study of phase equilibria in the PbO-CaO-AlO1.5 system in air","authors":"Georgii Khartcyzov,&nbsp;Maksym Shevchenko,&nbsp;Evgenii Nekhoroshev,&nbsp;Evgueni Jak","doi":"10.1111/jace.20351","DOIUrl":"https://doi.org/10.1111/jace.20351","url":null,"abstract":"<p>The present study focused on the phase equilibria in the PbO-CaO-AlO_1.5 and PbO-CaO systems in air. The high-temperature phase equilibria in these systems were studied using the high-temperature equilibration and quenching technique. The compositions of phases present in the quenched samples were then measured using the electron probe X-ray microanalysis. The liquidus of the PbO-CaO-AlO_1.5 system in air, including Ca₃Al₂O₆, Ca₁₂Al₁₄O₃₃, (Ca,Pb)Al₂O₄, CaAl₄O₇, (Ca,Pb)Al₁₂O₁₉, Ca₂PbO₄, corundum (Al₂O₃), lime (CaO), massicot (PbO), Pb₉Al₈O₂₁, PbAl₂O₄, and PbCa₂Al₈O₁₅ primary phase fields as well as the immiscibility gap in the liquidi of Ca₃Al₂O₆, Ca₁₂Al₁₄O₃₃, and (Ca,Pb)Al₂O₄ have been experimentally characterized. The experimental data obtained were used for the thermodynamic optimization of a self-consistent set of parameters of the thermodynamic model for all phases of the PbO-CaO-AlO_1.5 system in air, in agreement with the Cu-Pb-Zn-Fe-Ca-Si-Al-Mg-O-S-(As, Sn, Sb, Bi, Ag, Au, Ni, Cr, Co, and Na) gas/oxide liquid/matte/speiss/metal/solids system in support of the development and optimization of pyrometallurgical processes. The predicted liquidus projection of the PbO-CaO-AlO_1.5 system was presented for the first time in the complete range of temperatures and compositions.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143530154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantifying nano-domain size and orientation in relaxor ferroelectrics using transmission electron microscopy","authors":"Nathan M. Brichta,&nbsp;Levi Tegg,&nbsp;Luke W. Giles,&nbsp;John E. Daniels,&nbsp;Julie M. Cairney","doi":"10.1111/jace.20346","DOIUrl":"https://doi.org/10.1111/jace.20346","url":null,"abstract":"<p>Ferroelectric materials contain regions of uniform electrical polarization, known as domains. In Pb-based relaxor-ferroelectric perovskite oxides, these domains can be as small as a few nanometers, making standardized analysis of domain sizes challenging. Here, we present two methods for the quantitative analysis of domain sizes from transmission electron micrographs. One method uses statistical analysis of multiple line profiles, and the other analyses the intensity of streaks in the Fourier transform of the image. The techniques provide equivalent results for bright-field images free of other microstructure or aberrations, while the Fourier method is much simpler to apply.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143530153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced temperature stability of colossal-permittivity Ce-doped SrTiO3 ceramics designed by defect engineering","authors":"Mingliang Zhu,&nbsp;Kang Liu,&nbsp;Yingzhi Meng,&nbsp;Xuerui Qiang,&nbsp;Xiyue Xia,&nbsp;Xueli Cao,&nbsp;Xiuyun Lei,&nbsp;Dawei Wang,&nbsp;Laijun Liu","doi":"10.1111/jace.20365","DOIUrl":"https://doi.org/10.1111/jace.20365","url":null,"abstract":"&lt;p&gt;Cerium-doped SrTiO&lt;sub&gt;3&lt;/sub&gt; ceramics (Sr&lt;sub&gt;1-3&lt;/sub&gt;&lt;i&gt;&lt;sub&gt;x&lt;/sub&gt;&lt;/i&gt;&lt;sub&gt;/2&lt;/sub&gt;Ce&lt;i&gt;&lt;sub&gt;x&lt;/sub&gt;&lt;/i&gt;TiO&lt;sub&gt;3&lt;/sub&gt;, &lt;i&gt;x&lt;/i&gt; = 0, 0.005, 0.0075, 0.01, 0.0125, and 0.015) were prepared by a burying sintering process. The sample with &lt;i&gt;x&lt;/i&gt; = 0.0075 exhibits a colossal permittivity (∼ 21,000) and ultra-low dielectric loss (∼ 0.0073) at room temperature (at 1 kHz). Furthermore, the &lt;i&gt;x&lt;/i&gt; = 0.0075 sample maintains high permittivity (&lt;i&gt;ε&lt;/i&gt;′ ≥ 15,000) and low dielectric loss (tan&lt;i&gt;δ&lt;/i&gt; ≤ 0.018) in a wide temperature range (−60°C to 250°C). X-ray photoelectron spectroscopy and electron paramagnetic resonance indicate the coexistence of Ce&lt;sup&gt;3+&lt;/sup&gt; and Ti&lt;sup&gt;3+&lt;/sup&gt;. According to equation &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;C&lt;/mi&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mfrac&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;ε&lt;/mi&gt;\u0000 &lt;mi&gt;A&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mi&gt;d&lt;/mi&gt;\u0000 &lt;/mfrac&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$C = frac{{varepsilon A}}{d}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, synergetic effects from defect dipoles and interfacial polarization are responsible for the observed high-performance giant permittivity behaviors with pronounced temperature stability and ultralow tanδ. The dielectric behaviors under different DC biases evidence the minor contribution from the interfacial polarization and reflect the dominant contribution from defect dipoles. The dielectric properties of dielectric ceramics are mainly influenced by oxygen vacancy clusters and defect dipoles ((Ti&lt;sup&gt;3+&lt;/sup&gt; − &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;V&lt;/mi&gt;\u0000 &lt;mi&gt;O&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;•&lt;/mo&gt;\u0000 &lt;mo&gt;•&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;annotation&gt;${mathrm{V}}_O^{ bullet bullet }$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; − Ti&lt;sup&gt;3+&lt;/sup&gt;) and (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;V&lt;/mi&gt;\u0000 &lt;mi&gt;Sr&lt;/mi&gt;\u0000 &lt;msup&gt;\u0000 &lt;mrow&gt;&lt;/mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;′&lt;/mo&gt;\u0000 &lt;mo&gt;′&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;annotation&gt;${mathrm{V}}_{{mathrm{Sr}}}^{{mathrm{^{primeprime}}}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; − &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;V&lt;/mi&gt;\u0000 &lt;mi&gt;O&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;•&lt;/mo&gt;\u0000 &lt;mo&gt;•&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;annotation&gt;${mathrm{V}}_O^{ bullet bullet }$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;)). The excellent thermal stabilit","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143530313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced temperature stability and reduced tan δ in B-site modified titanate-based high-entropy perovskite oxides","authors":"Ketkaeo Bunpang,&nbsp;Widchaya Somsri,&nbsp;David P. Cann,&nbsp;Natthaphon Raengthon","doi":"10.1111/jace.20353","DOIUrl":"https://doi.org/10.1111/jace.20353","url":null,"abstract":"<p>The dielectric properties of complex titanate perovskites are highly sensitive to the composition, which influences the stability of the ferroelectric state. This work examines the role of Zr⁴⁺ and (Mg_1/3Nb_2/3)⁴⁺ doping on the B-site in a high entropy composition based on (Na_0.2Bi_0.2Ba_0.2Ca_0.2Sr_0.2)TiO₃. In particular, (Na_0.2Bi_0.2Ba_0.2Ca_0.2Sr_0.2)(Ti_1−xMe_x)O₃ (Me = Zr⁴⁺, (Mg_1/3Nb_2/3)⁴⁺, x = 0.00–0.15) ceramics are synthesized by solid-state reaction method. All ceramics form a single-phase cubic structure as demonstrated by X-ray diffraction. The difference in ionic radius between Zr⁴⁺ and (Mg_1/3Nb_2/3)⁴⁺ ions contributes to changes in lattice parameter and microstructure. The Zr⁴⁺ doping generally causes lattice expansion, whereas low concentrations of (Mg_1/3Nb_2/3)⁴⁺ doping lead to lattice contraction, resulting in distinct microstructural modifications. For the doped samples, the relative permittivity decreases due to the influence of the dopants when compared with the undoped sample. Furthermore, the dielectric loss decreases substantially to a value below 0.001 across a broad temperature range and the temperature stability of capacitance is enhanced at elevated temperatures. Furthermore, all ceramics with higher Zr⁴⁺ and (Mg_1/3Nb_2/3)⁴⁺ concentrations show linear dielectric behavior with evidence of significant change of electrical characteristics revealed by impedance and modulus analysis. Consequently, the addition of Zr⁴⁺ and (Mg_1/3Nb_2/3)⁴⁺ to the composition (Na_0.2Bi_0.2Ba_0.2Ca_0.2Sr_0.2)TiO₃ shows great promise for high temperature, temperature stable capacitor applications.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Triple-point phase diagrams for BTO-based ceramics","authors":"David Gracia,&nbsp;François Fauth,&nbsp;Sara Lafuerza,&nbsp;Marco Evangelisti,&nbsp;Javier Blasco","doi":"10.1111/jace.20366","DOIUrl":"https://doi.org/10.1111/jace.20366","url":null,"abstract":"<p>The temperature–composition structural phase diagram of the BTO-based ferroelectric system Ba_0.94Ca_0.06Ti₁₋<i>_x</i>Hf<i>_x</i>O₃ (0.05 ≤ <i>x</i> ≤ 0.15) is investigated using high-angular resolution synchrotron X-ray powder diffraction and dielectric permittivity measurements. In contrast to the well-known structural phase transition sequence of the parent compound BaTiO₃ (rhombohedral → orthorhombic → tetragonal → cubic, upon heating), Hf⁴⁺ doping into Ba_0.94Ca_0.06Ti₁₋<i>_x</i>Hf<i>_x</i>O₃ results in the gradual disappearance of the intermediate orthorhombic and tetragonal phases at two different, but close, critical concentrations, 0.10 &lt; <i>x</i>_c1 &lt; 0.12 and 0.12 &lt; <i>x</i>_c2 &lt; 0.135, respectively, revealing the presence of two triple points in the phase diagram.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jace.20366","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143530532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insights on proton-conducting ceramic electrochemical cell fabrication","authors":"Charlie Meisel,&nbsp;Jake D. Huang,&nbsp;You-Dong Kim,&nbsp;Sophia Stockburger,&nbsp;Ryan O'Hayre,&nbsp;Neal P. Sullivan","doi":"10.1111/jace.20321","DOIUrl":"https://doi.org/10.1111/jace.20321","url":null,"abstract":"<p>This study investigates the key factors influencing sintering behavior and grain growth in <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>BaCe</mi>\u0000 <mn>0.4</mn>\u0000 </msub>\u0000 <msub>\u0000 <mi>Zr</mi>\u0000 <mn>0.4</mn>\u0000 </msub>\u0000 <msub>\u0000 <mi>Y</mi>\u0000 <mn>0.1</mn>\u0000 </msub>\u0000 <msub>\u0000 <mi>Yb</mi>\u0000 <mn>0.1</mn>\u0000 </msub>\u0000 <msub>\u0000 <mi>O</mi>\u0000 <mrow>\u0000 <mn>3</mn>\u0000 <mo>−</mo>\u0000 <mi>δ</mi>\u0000 </mrow>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$mathrm{BaCe_{0.4}Zr_{0.4}Y_{0.1}Yb_{0.1}O_{3-delta }}$</annotation>\u0000 </semantics></math> (BCZYYb4411)–NiO negatrodes and BCZYYb electrolytes for protonic ceramic electrochemical cells (PCECs). Elastic net machine learning models are applied to a dataset of nearly 200 individual PCEC button cells fabricated over the course of more than 3 years to identify the key processing parameters that significantly affect negatrode shrinkage and electrolyte grain growth. The shrinkage rate of the BCZYYb4411–NiO negatrode is primarily governed by the solid-state sintering behavior. Higher sintering temperatures, longer dwell times, and smaller NiO particle size are the primary determinants that lead to greater shrinkage. New or lightly-used setters and more compact negatrodes are also found to increase shrinkage. Electrolyte grain growth is chiefly controlled by the liquid-phase sintering of the BCZYYb phase. Increased cerium content on the B-site leads to the largest enhancement in grain size, followed by increasing maximum sintering temperature. We find that the parameters used to tune the spray deposition of the electrolyte layer are also critical, with wetter and more uniform sprays promoting grain enlargement. Finally, we find that the sintering environment (e.g. presence/absence of sintering neighbors or sacrificial powders and the ambient humidity level) also substantially impacts both shrinkage and grain growth. This work comprehensively analyzes data from nearly 200 PCECs without “success bias,” meaning that poor performers and fabrication failures were included in the analysis. By doing so, the study provides valuable insight into the critical factors controlling shrinkage and grain growth in BCZYYb-based PCECs. The findings offer foundational guidance for processing optimization that could lead to better repeatability, increased yields, and higher performance.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of enhanced ferroelectric polarization through La doping on photovoltaic properties of BiFeO3 thin films on HOPG","authors":"Yoonho Ahn,&nbsp;Jong Yeog Son","doi":"10.1111/jace.20358","DOIUrl":"https://doi.org/10.1111/jace.20358","url":null,"abstract":"<p>BiFeO₃ (BFO) thin films are well-known for their multiferroic and photovoltaic properties, driving extensive research into potential applications. Highly ordered pyrolytic graphite (HOPG) substrates, with a graphene-like surface structure, provide an ideal platform for assessing the impact of graphene electrodes. This study investigates the photovoltaic properties of ITO/BFO/HOPG devices with La-doped BFO thin films at concentrations of 5, 10, and 15 mol%. The polycrystalline BFO thin films exhibited a preferential (111) orientation, with the 10 mol% La-doped thin films demonstrating optimal crystallinity and the highest remanent polarization of 50.8 µC/cm². Photovoltaically, the 5 mol% La-doped BFO thin film exhibited an open-circuit voltage (<i>V</i>_oc) of 0.46 V and the highest short-circuit current (<i>J</i>_sc) of 0.38 mA/cm². The 10 mol% La-doped BFO thin film achieved the highest <i>V</i>_oc of 0.57 V with a <i>J</i>_sc of 0.35 mA/cm², likely because of enhanced ferroelectric polarization. In contrast, the 15 mol% La-doped BFO thin film showed a reduced band gap but diminished photovoltaic performance. The minimal variation in the band gap (within 0.1 eV) suggests that the improved photovoltaic performance is primarily driven by increased polarization resulting from enhanced tetragonality.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fracture of ion-exchange-strengthened thin cover glass investigated using a phase-field model","authors":"Wei Wang,&nbsp;Jiaxuan Wang,&nbsp;Junjun Xu,&nbsp;Jianbiao Wang,&nbsp;Haihui Ruan","doi":"10.1111/jace.20367","DOIUrl":"https://doi.org/10.1111/jace.20367","url":null,"abstract":"<p>Ion-exchange-(IOX)-strengthened cover glass has been used ubiquitously in portable electronics to keep them from impact damage. However, a quantitative relation between residual-stress profile and fracture strength remains elusive because the experimental data are significantly scattered caused by the uncertainty in the severity of surface flaws. Therefore, we propose a phase-field fracture model (PFFM) to study the detailed fracture processes and the shielding effect of surface compressive stress (CS) on a pre-existing surface flaw. In particular, we discussed the strengthening efficiency due to different combinations of surface CS and the depth of layer (DOL) under compression based on the ring-on-ring (ROR) and ball-drop (BD) tests. The simulated contour maps of fracture strength and BD height indicate that in ROR experiments, a higher surface CS is more decisive in crack inhibition and that in BD experiments, DOL is more important.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143530533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}