Structural, dielectric, impedance, and electric modulus characteristics of Y₂CaCuO₅ high-k dielectric ceramics

Abstract

With the increasing trends of integrated circuit densification, device miniaturization, and exponential growth of microelectronic components there is a huge responsibility on the part of material researchers to derive, design, and develop new materials. Materials that can overcome the existing limitations in the present compounds available in the market or can expedite the process of material fabrication are of great interest. This feat can be achieved by the fabrication of new materials, and analysis of various characterizations viz. (structural, dielectric, transport behavior, and impedance spectroscopy). With this perspective, in this communication, a high permittivity dielectric material belonging to the Y-Ba-Cu-O ternary systems where barium is replaced by calcium (Y₂CaCuO₅) is synthesized using solid-state reaction route. X-ray diffraction, scanning electron micrograph, and energy-dispersive X-ray spectroscopic study confirm the phase and microstructure of the sample. The observed higher value of the dielectric constant is understood from Koop’s phenomenological theory and internal barrier layer capacitance model. The dispersive behavior of conductivity is interpreted by Jonscher’s power law. Overlapping large polaron tunneling model for conduction is observed. Impedance spectroscopy analysis reveals non-Debye type of relaxation with variable time constants. According to Nyquist plots; up to 250 °C only grain effect (bulk) is dominantly present; however, at higher temperatures, the contribution from both grain and grain boundary is seen.

Keywords:

• Impedance spectroscopy
• OLPT model
• modulus study
• Nyquist plot
• Koop’s theory

Acknowledgments

One of the authors Rashmi Rekha Sahoo would like to acknowledge DST, GOI, for INSPIRE fellowship. The authors acknowledge OUAT, Bhubaneswar for providing a few experimental characterizations.

Disclosure statement

The authors declare that there are no known competing interests.

Table 1. Details of grain and grain boundary resistance, capacitance, and CPE values.