Synthesis and ferroelectric properties of bismuth layer-structured (Bi7−xSrx)(Fe3−xTi3+x)O21 solid solutions

Structural Evolution and Multiferroics in Sr‐Doped Bi7Fe1.5Co1.5Ti3O21 Ceramics

“…(a), consistent with the result in Ref. . The layer number of the main phase decreases gradually, while the amount of the secondary phase arises with the increase of Sr content.…”

“…The substitution of divalent Sr ion at the trivalent Bi sites in SBFCT may influence the magnetic property in two ways. One is that the difference between effective ionic radii Sr 2+ (1.26 Å) and Bi 3+ (1.17 Å) will generate the distortion of B O 6 octahedron . The other is the valence state difference between Sr 2+ and Bi 3+ .…”

“…The naturally layered perovskite‐like “superlattice” 2D nanostructure of such materials gives the possible coexistence of cations with unoccupied d ‐orbital and partially filled d ‐orbital in harmony. Furthermore, in Sr 2+ ‐doped compound (Bi 7− x Sr x )(Fe 3− x Ti 3+ x )O 21 ( n = 6), a 2 P r of ~60 μC/cm 2 at an applied voltage of 280 kV/cm was obtained, which is the maximum 2 P r reported in Aurivillius compounds, and can satisfy the practical application needs . Therefore, Sr 2+ –Co 3+ codoping is one of the best choices for ion‐doped (Bi 2 O 2 ) 2+ {Bi n −1 (Fe) n− 3 Ti 3 O 3 n +1 } 2− (BFTO) compounds and would accelerate the application process of such single phase multiferroic materials.…”

Cobalt-Substituted Seven-Layer Aurivillius Bi8Fe4Ti3O24 Ceramics: Enhanced Ferromagnetism and Ferroelectricity

“…Researchers have already revealed the coupled FE and the unwanted antiferromagnetic (AFM) behaviors in such compounds with n = 4 (4-BFTO) [8-10], 5 (5-BFTO) [11][12][13], and 6 (6-BFTO) [14,15]. In 2009, with Co partially substituted for Fe, a new Bi5Fe0.5Co0.5Ti3O15 (4-BFCT) ceramic was investigated for the first time, which was found able to present a significant coexistence of FE and FM well above room temperature.…”

“…Furthermore, (Bi 2 O 2 ) 2+ layers in Bi 4 Ti 3 O 12 can play the key role as both space-charge compensation and insulation, with an expectation to be able to further reduce the leakage and improve fatigue properties as well [7]. Researchers have already revealed the coupled FE and the unwanted antiferromagnetic (AFM) behaviors in such compounds with n = 4 (4-BFTO) [8][9][10], 5 (5-BFTO) [11][12][13], and 6 (6-BFTO) [14,15]. In 2009, with Co partially substituted for Fe, a new Bi 5 Fe 0.5 Co 0.5 Ti 3 O 15 (4-BFCT) ceramic was investigated for the first time, which was found able to present a significant coexistence of FE and FM well above room temperature.…”