Intriguing structural and magnetic properties correlation study on Fe3+-substituted calcium-copper-titanate

• Published in: Physical chemistry chemical physics : PCCP 2018-01, Vol.20 (3), p.1914-1922
• Main Authors: Pansara, P R, Raval, P Y, Vasoya, N H, Dolia, S N, Modi, K B
• Format: Article
• Language: English
• Subjects: Antiferromagnetism; Calcium titanate; Copper; Correlation analysis; Ferromagnetism; Iron 57; Magnetic properties; Mossbauer spectroscopy; Quadrupoles; Splitting; Substitutes; Superconducting quantum interference devices; Symmetry
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c7cp06681c

This communication presents a detailed study on a Fe3+ modified CaCu3Ti4O12 cubic perovskite system (CaCu3−xTi4−xFe2xO12 with x = 0.0–0.7) by performing X-ray powder diffractometry, DC SQUID magnetization and 57Fe Mössbauer spectroscopy. The first ever Mössbauer studies on the system supported the reported peculiarity of the structure. Mössbauer analysis for the compositions x = 0.1, 0.3, and 0.5 suggest Fe3+ ions in two different environments. The site with larger quadrupole splitting corresponds to Fe3+ in the octahedral symmetry, while the site with lower chemical shift and quadrupole splitting belongs to Fe3+ in the square-planar (A′-) configuration. With the increase in Fe-substitution, Fe3+ appears to prefer A′- symmetry. Antiferromagnetic features are retained up to x = 0.3, but weak ferromagnetic characteristics appear with higher Fe3+ substitution. The switching of antiferromagnetic to ferromagnetic behavior was related to the preferential occupation of Fe3+ in square-planar symmetry accommodating Cu2+.