Dielectric Behavior of alpha-Ag2WO4 and its Huge Dielectric Loss Tangent

Author(s)

Jacomaci, Natalia ^[1] ; Silva Junior, Euripedes ^[1] ; Borges de Oliveira, Fernando Modesto ^[2] ; Longo, Elson ^[2] ; Zaghete, Maria Aparecida ^[1]

Affiliation

^[1] Univ Estadual Paulista, UNESP, Inst Quim, BR-14800060 Araraquara, SP - Brazil

^[2] Univ Fed Sao Carlos UFSCar, Dept Quim, BR-13565905 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: MATERIALS RESEARCH-IBERO-AMERICAN JOURNAL OF MATERIALS; v. 22, n. 4 2019.
• Web of Science Citations: 0

Abstract

The microwave-assisted hydrothermal method was used to obtain alpha-Ag2WO4. Rietveld refinement confirmed that alpha-Ag2WO4 is stable in the orthorhombic phase, without secondary phase. However, field-effect scanning electron microscope analysis showed that alpha-Ag2WO4 nanorods surfaces contain silver nanoparticles, confirmed by the X-ray photoelectron spectroscopy by the peak observed at 374.39 eV In addition to metallic Ag, other Ag oxidation states were also observed on the surface. Hence, Ag (I) as Ag2O and Ag (I) as Ag(2)WO(4 )also were identified. DC measurements exhibited a high capacity of charge storage, nevertheless, with a large loss tangent (0.12 mu C.cm(-2).V-1) and no residual polarization for the voltage range between -100 V and +100 V. AC measurements at frequencies less than 275 Hz, revealed that ionic polarization is dominant, whereas at frequencies higher than 275 Hz, the electronic behavior predominates. The potential of electromagnetic energy conversion in thermal was observed from loss tangent analysis. (AU)

• 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