Mössbauer Study of the Dynamics in BaFe₁₂O₁₉Single Crystals

Abstract

Mössbauer spectra of hexagonal BaFe 12 O 19 single crystals were studied at various temperatures (4-300 K). It was found that the spin states in Fe atoms were parallel to the γ-ray's direction into a single crystal along the caxis. The location of the Fe ion in the 2b site is unusual in an oxide structure and has strong anisotropic lattice vibrations. Moreover, at room temperature, the zero absorption lines of the Fe ions at the 2b site were observed due to fast diffusion motion in a double well atomic potential. The two Fe ions of the single crystal mainly enter into the sites in the mirror plane of the trigonalbipyramidal structure.

Microscopic Mechanism of Ferroelectric Properties in Barium Hexaferrites

“…Others mechanisms of induction of remnant polarization are associated with the appearance of a noncollinear magnetic structure in solid solutions of M-type hexaferrites [9,10,11] or as a result of displacement of F e ion from the center of trigonal bipyramid 2b(4e) [14,15]. Moreover, noticeable displacements of Fe ions from the center of the trigonal bipyramid are observed in many experiments [13,16,17] and explained with the quantum paraelectricity nature of barium hexaferrite in Ref. [18].…”

Microscopic mechanism of ferroelectric properties in barium hexaferrites

“…Others mechanisms of induction of remnant polarization are associated with the appearance of a noncollinear magnetic structure in solid solutions of M-type hexaferrites [9,10,11] or as a result of displacement of F e ion from the center of trigonal bipyramid 2b(4e) [14,15]. Moreover, noticeable displacements of Fe ions from the center of the trigonal bipyramid are observed in many experiments [13,16,17] and explained with the quantum paraelectricity nature of barium hexaferrite in Ref. [18].…”