Oxygen octahedra distortion induced structural and magnetic phase transitions in Bi{sub 1−x}Ca{sub x}Fe{sub 1−x}Mn{sub x}O{sub 3} ceramics

Journal Article · Thu May 21 00:00:00 EDT 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4921433· OSTI ID:22410215

Kumar, Pawan; Kar, Manoranjan ^[1]; Shankhwar, Nisha; Srinivasan, A. ^[2]

---

1. Department of Physics, Indian Institute of Technology Patna, Patna 800013 (India)
2. Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039 (India)

The co-doping of Ca and Mn in respective Bi and Fe-sites of BiFeO{sub 3} lattice leads to structural transition from rhombohedral (R3c space group) to orthorhombic (Pbnm space group) crystal symmetry. The tilt angle for anti-phase rotation of the oxygen octahedra of BiFeO{sub 3} at room temperature is observed to be ∼13.8°. It decreases with the increase in the co-doping percentage which suggests the composition-driven structural phase transition. The remnant magnetization for sample with 15% of co-doping becomes about 16 times that of BiFeO{sub 3}. It may be attributed to the suppression of cycloid spin structure and uncompensated spins at the surface of nanocrystallites. Further increase in co-doping percentage results in the sharp reduction of remnant magnetization due to the dominant contribution from the collinear antiferromagnetic ordering in the Pbnm space group. The Arrott plot analysis clearly indicates the composition-driven crossover from the antiferromagnetic to weak ferromagnetic ordering and vice versa. Electron spin resonance results provide the evidence for the composition-driven phase transitions from an incommensurate spin cycloidal modulated state to one with nearly homogeneous spin order. The band gap (2.17 eV) of BiFeO{sub 3} measured using UV-Vis spectra was supported by the resonance Raman spectra.

• OSTI ID: 22410215
• Journal Information: Journal of Applied Physics, Vol. 117, Issue 19; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANTIFERROMAGNETISM
BISMUTH COMPOUNDS
CALCIUM COMPOUNDS
CERAMICS
CRYSTALS
ELECTRON SPIN RESONANCE
EV RANGE
FERRITES
MAGNETIZATION
MANGANESE COMPOUNDS
ORTHORHOMBIC LATTICES
PHASE TRANSFORMATIONS
RAMAN SPECTRA
SURFACES
TEMPERATURE RANGE 0273-0400 K
TRIGONAL LATTICES
ULTRAVIOLET SPECTRA
VISIBLE SPECTRA