Neutron diffraction study of BiFeO3 and BiFe0.98Co0.02O3 nano-particles. (October 2015)

• Record Type: Journal Article
• Authors: Ray, J.; Biswal, A.K.; Babu, P.D.; Siruguri, V.; Vishwakarma, P.N.
• Is Part Of: Solid state communications. Volume 220(2015)
• Page Start: 57
• Page End: 60
• Publication Date: 2015-10
• Subjects: C. Neutron diffraction -- D. Anharmonic cycloidal magnetic structure -- D. Spin state transition; Solid state chemistry -- Periodicals; Solid state physics -- Periodicals; Chimie de l'état solide -- Périodiques; Physique de l'état solide -- Périodiques; 530.41
• DOI: 10.1016/j.ssc.2015.07.009
• Languages: English
• ISSNs: 0038-1098

Abstract

Abstract: Nano particles of BiFeO3 and BiFe0.98 Co0.02 O3 are studied via neutron diffraction technique. Analysis of purely magnetic peak near d ~ 4.56 Å, reveals large spin canting and anharmonic cycloidal magnetic structure i.e., bunching of the magnetic moment along c-axis at 300K. This is in contrary to that observed in bulk, where the spins are restricted to ab-plane only. The substitution of Co 3+ is found to be inducing more spin canting. On decreasing the temperature, magnetic anharmonicity decreases and the magnetic cycloidal structure revives. At room temperature, the Co 3+ are found to be in intermediate spin state corresponding to magnetic moment 2.828 μB, whereas that of Fe 3+ as 3.848 μB . At low temperatures, signature of spin state transition from intermediate spin (S =1) to low spin (S = 0) of Co 3+ ion is observed. Highlights: G-type antiferromagnetic order with spin canting out of ab-plane in BiFeO3 . Bunching of spins along c-axis for Cobalt doped BiFeO3 . Anharmonicity in spin cycloid is suppressed at low temperature. Spin state transitions due to Cobalt doping at T <100 K.