Tuning dielectric and nonohmic properties of CaCu₃Ti₄O₁₂ ceramics with W doping

Author(s)

Moreno, H. ; Teixeira, V. C. ; Ponce, M. A. ; Macchi, C. E. ; Aldao, C. M. ; Bezzon, V. D. N. ; Simoes, A. Z. ; Ramirez, M. A.

• Document type: Journal article
• Source: Materials Research Bulletin; v. 190, p. 14-pg., 2025-04-19.

Abstract

This study investigates the dielectric and nonohmic properties of the CaCu3Ti4O12: x % W (x = 0.00, 0.02, 0.010, 2.50, 5.00) denoted as CCTO, W002, W010, W250, and W500, respectively. X-ray diffraction analysis confirmed a pseudo-cubic perovskite phase (Im-3 space group) for samples, and a CaCu3Ti4O12/CaWO4/TiO2 composite system for high W content (W250, W500), supported by energy dispersive spectroscopy (EDS) and X-ray fluorescence (XRF) measurements. Positron annihilation lifetime spectroscopy identified V-Cu ''/V-Ca '' vacancies as the main defects induced by W incorporation, influencing charge carrier mobility at grain boundaries, thus affecting sintering, grain size, and morphology. Lower W content (W002) resulted in a high dielectric response (epsilon similar to 1.2 x 10(4)) with improved tan delta (0.02). Conversely, W250 exhibited higher nonlinear coefficient (alpha similar to 38), with low leakage current (I-L similar to 14.6 mu A/cm(2)) and breakdown voltage (Eb similar to 198 V. cm(-1)). This solid-state synthesis method provides a way to customize TiO2/CaWO4-doped CCTO matrices, showcasing promising varistor characteristics that are well-suited for hybrid capacitor-varistor devices and related applications. (AU)

• FAPESP's process: 18/18236-4 - Development of advanced CaCu3Ti4O12 ceramics in the form of powders, bulks, and nanostructured films: an integrated studied of its multifunctional properties
• Grantee: Henrique Piccoli Moreno
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 19/27053-3 - Advances in rigid and flexible multi-functional nanocomposites based on perovskites modified with reduced graphen oxide for electro-electronic applications
• Grantee: Miguel Ángel Ramírez Gil
• Support Opportunities: Regular Research Grants
• FAPESP's process: 23/11583-9 - Development of Ag2SeO3-based semiconductors for antibiotic photodegradation: an innovative approach to enhance effluent treatment technologies
• Grantee: Henrique Piccoli Moreno
• Support Opportunities: Scholarships in Brazil - Post-Doctoral