Observed, calculated, and difference X-ray diffraction patterns obtained for the Bi0.92Nd0.08Fe1−xMnxO3 (x = 0.1 (a), x = 0.15 (b), and x = 0.2 (c)) compounds at room temperature. The antiferroelectric phase of the phase-separated x = 0.2 sample was described in the approximation of commensurate orthorhombic structure with the space group Pbam (see Refs. 19 , 20 , 22–26 for more details). Inset shows backscattered electron image of the Bi0.92Nd0.08Fe0.85Mn0.15O3 ceramics.
Atomic arrangement in the “Pm m” (a) and “R3c” (b) structures along the axis coincident with one of the ⟨100⟩c directions of the parent cubic perovskite cell. Representation of the rhombohedral structure is based on the refined parameters obtained for the Bi0.92Nd0.08Fe0.9Mn0.1O3 compound (Table I ).
Concentrational dependences of the unit cell volume (black squares), polarization (blue circles) and polar displacements of the O2− (white bars) and ⟨Fe/Mn⟩3+ (red bars) ions for the single-phase rhombohedral Bi0.92Nd0.08Fe1−xMnxO3 (x ≤ 0.15) compounds at room temperature.
Scanning probe microscopy measurements of the Bi0.92Nd0.08Fe0.85Mn0.15O3 ceramics: topography (a), electric-field-induced PFM contrast after poling with Vdc = 60 V (dark spot) and Vdc = −60 V (bright spots), and local piezoresponse hysteresis loops obtained from the surface of two different grains (c).
Field dependences of the magnetization obtained for the Bi0.92Nd0.08Fe1−xMnxO3 compounds at room temperature.
Compositional dependence of the remanent/spontaneous magnetization for the rhombohedral (close symbols)/orthorhombic (open symbols) compounds of the Bi0.92Nd0.08Fe1−xMnxO3 (x ≤ 0.3) system at room temperature. The color-marked regions composing the eye-guide curve separate the AF polar phase (red dotted line), wF nonpolar phase (blue solid line), and intermediate polar phase in which the change of the dominant magnetic state occurs (green dashed line). Straight line indicates the spontaneous magnetization expected for the Bi0.92Nd0.08Fe1−xMnxO3 compounds upon removal of the cycloidal modulation.
Structural parameters of the Bi0.92Nd0.08Fe0.9Mn0.1O3 compound at room temperature (space group R3c).
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