Detail investigation of thermoelectric performance and magnetic properties of Cs-doped Bi2Sr2Co2Oy ceramic materials


Ozcelik B. , Gursul M. , Cetin G. , Ozcelik C., Torres M. A. , Madre M. A. , ...More

SN APPLIED SCIENCES, vol.3, no.1, 2021 (Journal Indexed in ESCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 3 Issue: 1
  • Publication Date: 2021
  • Doi Number: 10.1007/s42452-020-04066-2
  • Title of Journal : SN APPLIED SCIENCES
  • Keywords: Bi2Sr2Co2Oy, Electrical properties, Seebeck coefficient, Power factor, Layered cobaltites

Abstract

Bi2Sr2-xCsxCo2Oy materials with 0 <= x <= 0.15, have been fabricated via the classical ceramic technique. XRD results have indicated that undoped and Cs-substituted samples are composed of Bi2Sr2Co2Oy phase as the major one. Microstructural studies have demonstrated the formation of a liquid phase, which allows a drastic grain growth. This factor is responsible for a drastic improvement of relative density, reaching about 95% of the theoretical one for 0.125 Cs content. On the other hand, electrical resistivity has been reduced up to 14 m Omega cm at 650 degrees C for 0.125 Cs content, around 40% lower than the obtained in undoped samples. As a consequence, Seebeck coefficient has been decreased due to the raise in charge carrier concentration. The highest power factor at 650 degrees C (0.21 mW/K-2 m) has been found for 0.125 Cs substituted sample, about 40% larger than the obtained in undoped samples, and very similar to the notified in single crystals (0.26 mW/K-2 m). Magnetisation with respect to temperature results have demonstrated that measured samples have a paramagnetic property above 50 K, except 0.10 Cs. Magnetic hysteresis curves have shown that the slopes and the magnitudes have increased with decreasing temperature.