Dielectric and electrical properties of polymorphic bismuth pyrostannate Bi2Sn2O7

Correlation of the magnetic and transport properties with polymorphic transitions in bismuth pyrostannate Bi2(Sn1 − x Cr x )2O7

“…The next effect, which is accompanied by the absorption of heat at 548 K, suggests another phase transition, in which the orthorhombic phase completely transforms into the cubic phase. In the vicinity of this temperature, anom alies were revealed in the temperature dependences of the imaginary part of the permittivity and the electrical resistance of Bi 2 Sn 2 O 7 [10]. The third distinct endot hermic peak at T = 872 K is reversible.…”

“…In the Bi 2 (Sn 0.9 Cr 0.1 ) 2 O 7 solid solution, the substitution of chromium for tin causes a shift of the boundaries of the phase transition from the orthorhombic to cubic state toward the low temperature range up to T = 445 K. In the high temperature range, the dependences have two portions in the regions of the temperatures T = 570 and 670-720 K, which are characterized by a change in the activation energy. The activation ener gies calculated from the linear dependence logρ(10 3 /T) on the inverse temperature for Bi 2 (Sn 0.9 Cr 0.1 ) 2 O 7 are as follows: ΔE 1 = 0.6 eV in the temperature range of 450-570 K and ΔE 2 = 0.8 eV in the temperature range of 570-650 K, which is higher than the activation energy ΔE = 0.23 eV for Bi 2 Sn 2 O 7[10].…”

“…The initial oxide mixture pressed into pellets was placed in a fur nace and heated at temperatures in the range from 700 to 950°C. The exposure time was varied from 8 to 24 h. The X ray diffraction analysis of the synthesized sam ples showed that the compound does not contain impurities and has two polymorphic (tetragonal and orthorhombic) modifications, which exist simulta neously; moreover, the percentage of the tetragonal phase is higher than that of the orthorhombic phase, as in the Bi 2 Sn 2 O 7 compound [10]. The X ray diffraction pattern of Bi 2 (Sn 1 -x Cr x ) 2 O 7 with x = 0.1 is shown in Fig.…”

“…The IR spectrum of Bi 2 Sn 2 O 7 [9] differs significantly from typical spectra of stannates with a cubic structure of the pyrochlore type. In Bi 2 Sn 2 O 7 , two polymorphic (orthorhombic and cubic) modifications can exist simultaneously [10].…”

Interaction of Magnetic and Dielectric Subsystes in a Bismuth Nodymic Ferrite-Granate

“…Introduction. Multiferroics attract interest both from the practical, and from the fundamental point of research of interaction mechanisms between magnetic and electric subsystems [1][2][3][4][5].…”