Enhanced dielectric properties with a significantly reduced loss tangent in (Mg2+, Al3+) co-doped CaCu3Ti4O12ceramics: DFT and experimental investigations

Boonlakhorn, Jakkree; Manyam, Jedsada; Krongsuk, Sriprajak; Thongbai, Prasit; Srepusharawoot, Pornjuk

doi:10.1039/d1ra02896k

Cited by 15 publications

(14 citation statements)

References 49 publications

(121 reference statements)

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“…The Ti 3+ /Ti 4+ ratio was 2.37/97.63 and 2.69/97.31% for NY9h and NY15h, respectively. The presence of Cu + and Ti 3+ is in agreement with earlier literature reports 30 , 34 . Cu + and Ti 3+ in the NYCTO lattice indicates the presence of V O in the structure.…”

Section: Discussionsupporting

confidence: 93%

“…Hence, Na + is likely to occupy Cu 2+ sites. This observation is confirmed by earlier experimental and theoretical investigations 34,[40][41][42] . As demonstrated by Li et al 43 , Ti 4+ ions can reduce their oxidation state to Ti 3+ .…”

Section: Discussionsupporting

confidence: 89%

“…www.nature.com/scientificreports/ temperature over the same frequency range. The dielectric behavior in this frequency range may be attributed to DC conduction induced at GBs and other factors, such as the sample-electrode contact 34 . At frequencies greater than 10 5 Hz, a fast reduction of ε′ is observed, which corresponds to the rapid increase in the ε″ value at the same frequencies.…”

Section: Discussionmentioning

confidence: 97%

“…For NYCTO ceramics, a small conductivity (within the grains) due to electron hopping between Cu + ↔Cu 2+ and Ti 3+ ↔Ti 4+ might play an important role in the colossal dielectric response of this material. According to previous studies, variation of dielectric response can be controlled by metal-ion doping 34 , 42 in the ceramic lattice or annealing at various atmospheres 45 .…”

Section: Discussionmentioning

confidence: 99%

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Computational and experimental investigations of the giant dielectric property of Na1/2Y1/2Cu3Ti4O12 ceramics

Boonlakhorn

Suksangrat

Sarakorn

et al. 2023

Sci Rep

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A modified sol-gel method was used to successfully produce Na1/2Y1/2Cu3Ti4O12 ceramics with high dielectric permittivity. The dielectric permittivity of Na1/2Y1/2Cu3Ti4O12 ceramics reaches values larger than 104 at room temperature and 1 kHz. Moreover, these ceramics exhibit two distinct thermally induced dielectric relaxations over a broad temperature range. The loss tangent is indeed small, ~0.032–0.035. At low temperatures, dielectric relaxation was attributed to the oxygen vacancy effect, while at high temperatures, it was attributed to grain boundary and sample-electrode contact effects. Our calculations revealed that Y and Na ions are likely to occupy Ca and Cu sites, respectively. As a result, other Cu related phases, especially CuO, were observed at the grain boundaries. Based on our analysis, there is a charge compensation between Na and Y ions in Na1/2Y1/2Cu3Ti4O12. Additionally, the Cu+ and Ti3+ states observed in our XPS study originate from the presence of an oxygen vacancy in the lattice. Last, the primary cause of the enormous dielectric permittivity of Na1/2Y1/2Cu3Ti4O12 ceramics primarily comes from the internal barrier layer capacitor effect.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

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Computational and experimental investigations of the giant dielectric property of Na1/2Y1/2Cu3Ti4O12 ceramics

Boonlakhorn

Suksangrat

Sarakorn

et al. 2023

Sci Rep

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“…In our previous study [34], we performed calculations on the formation energies associated with substitution of an Al atom at Ca, Cu, or Ti sites within CaCu 3 Ti 4 O 12 . Our findings revealed formation energies of +4.41 eV, −3.25 eV, and +1.44 eV for Al substitution at the Ca, Cu, and Ti sites, respectively.…”

Section: Resultsmentioning

confidence: 99%

Dielectric properties of the Ca_0.25Cu_0.75-xAl_xTiO₃ ceramics: experimental and computational investigations

Boonlakhorn,

Suksangrat,

Srepusharawoot

2024

Mater. Res. Express

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In this study, we employed a solid-state reaction method to synthesize Ca0.25Cu0.75-xAlxTiO3 ceramics, investigating the impact of Al doping at concentrations of x=0 and 0.0125. Notably, all ceramics exhibited a primary phase of Ca0.25Cu0.75TiO3. The addition of Al3+ induced a significant increase in grain size. Density functional theory analyses revealed a preferential occupation of Cu sites by Al, leading to liquid-phase sintering processes attributed to excess Cu. Moreover, it was also found from DFT that the Al dopant cannot induce an oxygen vacancy in the lattice. Charge density analysis revealed that Cu+ and Ti3+ observed via XPS originate from the presence of an oxygen vacancy. The Ca0.25Cu0.7375Al0.0125TiO3 ceramic exhibited a very high dielectric permittivity of 9.23×104 and a low dielectric loss tangent of 0.057 at 1 kHz and room temperature. Importantly, the dielectric permittivity exhibited impressive stability over a temperature range of -60 °C to 110 °C, perfectly meeting the practical requirements for utilization in X6R ceramic capacitors. Our investigation indicates that the improved dielectric properties may be attributed to enhanced grain boundary responses, influenced by oxygen enrichment and the presence of metastable insulating layers at grain boundaries. Combining experimental findings with theoretical evidence, our study elucidates that the excellent dielectric properties of the Ca0.25Cu0.7375Al0.0125TiO3 ceramic originate from an extrinsic effect arising from grain boundary enhancement. This work not only contributes to advancing the understanding of the underlying mechanisms governing dielectric behavior in doped ceramics, but also emphasizes the potential of Ca0.25Cu0.7375Al0.0125TiO3 as a promising material for applications demanding superior dielectric performance.

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Calcium copper titanate a perovskite oxide structure: effect of fabrication techniques and doping on electrical properties—a review

Infantiya

Aslinjensipriya

Reena

et al. 2022

J Mater Sci: Mater Electron

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Enhanced dielectric properties with a significantly reduced loss tangent in (Mg²⁺, Al³⁺) co-doped CaCu₃Ti₄O₁₂ceramics: DFT and experimental investigations

Abstract: Mg and Al atoms preferentially occupy Cu sites, creating liquid-phase sintering decomposition at grain boundary layers. This results in very high dielectric permittivity and a low loss tangent of the CaCu2.95Mg0.05Ti3.95Al0.05O12 ceramic.

Cited by 15 publications

References 49 publications

Computational and experimental investigations of the giant dielectric property of Na1/2Y1/2Cu3Ti4O12 ceramics

Computational and experimental investigations of the giant dielectric property of Na1/2Y1/2Cu3Ti4O12 ceramics

Dielectric properties of the Ca_0.25Cu_0.75-xAl_xTiO₃ ceramics: experimental and computational investigations

Calcium copper titanate a perovskite oxide structure: effect of fabrication techniques and doping on electrical properties—a review

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Enhanced dielectric properties with a significantly reduced loss tangent in (Mg2+, Al3+) co-doped CaCu3Ti4O12ceramics: DFT and experimental investigations

Abstract: Mg and Al atoms preferentially occupy Cu sites, creating liquid-phase sintering decomposition at grain boundary layers. This results in very high dielectric permittivity and a low loss tangent of the CaCu2.95Mg0.05Ti3.95Al0.05O12 ceramic.

Cited by 15 publications

References 49 publications

Computational and experimental investigations of the giant dielectric property of Na1/2Y1/2Cu3Ti4O12 ceramics

Computational and experimental investigations of the giant dielectric property of Na1/2Y1/2Cu3Ti4O12 ceramics

Dielectric properties of the Ca0.25Cu0.75-xAlxTiO3 ceramics: experimental and computational investigations

Calcium copper titanate a perovskite oxide structure: effect of fabrication techniques and doping on electrical properties—a review

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Enhanced dielectric properties with a significantly reduced loss tangent in (Mg²⁺, Al³⁺) co-doped CaCu₃Ti₄O₁₂ceramics: DFT and experimental investigations

Dielectric properties of the Ca_0.25Cu_0.75-xAl_xTiO₃ ceramics: experimental and computational investigations