Stabilization of 6H-Hexagonal SrMnO3 Polymorph by Al2O3 insertion. Issue 10 (August 2021)

• Record Type: Journal Article
• Authors: Sheeraz, Muhammad; Rashid, Mamoon Ur; Ali, Asad; Akram, Fazli; Lee, Ho Jeong; Choi, Jin San; Bae, Jong-Seong; Kim, Yong Soo; Shin, Young-Han; Ahn, Chang Won; Kim, Tae Heon
• Is Part Of: Journal of the European Ceramic Society. Volume 41:Issue 10(2021)
• Page Start: 5155
• Page End: 5162
• Publication Date: 2021-08
• Subjects: Ceramics -- Oxide -- Structural phase transition -- X-ray diffraction; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2021.03.060
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: We demonstrate the structural evolution of polymorphic phases in Al2 O3 -inserted SrMnO3 ceramics synthesized by solid state reaction. While the 4H-hexagonal phase is predominant in pure SrMnO3 ceramics, a small amount of 6H-hexagonal polymorph is identified in addition to the primary 4H-hexagonal SrMnO3 and the secondary hexagonal SrAl2 O4 phases in the as-sintered ceramics, evidenced by x-ray diffraction and subsequent Rietveld refinement analyses. The existence of the 6H-hexagonal SrMnO3 phase is corroborated using Raman spectroscopy. The chemical compositions and electronic structures of the Al2 O3 -inserted SrMnO3 compounds are also examined using energy dispersive spectroscopy and x-ray photoelectron spectroscopy, respectively. The first-principles calculations reveal that there is no clear difference between the total energies of 4H- and 6H-hexagonal polymorphs regardless of the presence/absence of Sr and oxygen vacancies. Possible origins are discussed with the estimation of actual strain based on the refined lattice parameter of 6H SrMnO3 .