Sr 2 SbMnO 6 : A new semiconductor ferroelectric

Abstract

Sr 2 SbMnO 6 is predicted to be ferroelectric with Curie temperature Tc=450(175) K on the basis of a 1990 structure determination. Calorimetry reveals a stepwise heat capacity change at Tc=431(5) K, indicative of a phase transition close to first order. A further small calorimetric anomaly occurs reproducibly at 743(10) K, consistent with an earlier report of a higher-temperature phase transition to cubic symmetry. The dielectric permittivity ε′ increases sharply at Tc=466(10)K in the range 0.1–100 kHz; ε′ rises ∼3 orders of magnitude at 0.1 kHz, ∼1.0 order at 100 kHz, before a stable maximum is reached at T>Tc. The conductivity σ of Sr2SbMnO6 at 295 K is 0.23(5) S m−1, too high for dielectric hysteresis measurement. The linear dependence of ln σ on 1/T between 295 K and Tc in this semiconductor ferroelectric corresponds to a band-gap EG=0.50(2) eV; above Tc, EG increases abruptly to 0.70(2) eV.

Integration of first-principles methods and crystallographic database searches for new ferroelectrics: Strategies and explorations

“…[55], but has a nonpolar structure, as reported in subsequent papers for both disordered and partially ordered cases. This negative result, though disappointing when considered in the framework of the discovery of new ferroelectric materials, does illustrate the value of including first principles results in evaluating structural data.…”

“…A value for the band gap of 0.50(2) eV was extracted from the Arrhenius behavior of the conductivity in Ref. [55] (in which the space group was reported to be polar I4mm, consistent with Ref. [56]).…”

“…In this case, the database search was performed not by us, but previously by Abrahams [37] as part of a large-scale research program to identify previously-overlooked ferroelectric materials in the ICSD. This search resulted in the identification of a number of candidate ferroelecrics, including the double perovskite Sr(Sb 1/2 Mn 1/2 )O 3 [55] ; this system was of particular interest to us because onehalf of the octahedral units contain a main group element (Sb) which could promote a lower band gap, making the system a ferroelectric semiconductor. In addition, the presence of the transition metal Mn could lead to magnetic and multiferroic behavior.…”

“…[56], as given in Table 1 of Ref. [55], combined with an additional oxygen octahedron rotation around z, alternating from plane to plane, taken from Ref. [57].…”

Theoretical study of structural stability and electronic properties of Sr2MnSbO6 perovskite

“…The Sr 2 MnSbO 6 perovskite is one compound of this type, and it has been synthetized via molten salt synthesis (MSS) method and convectional solid-state methods for example by (Cheah et al, 2006;Ivanov et al, 2009;Parada et al, 2018;Preethi-Meher et al, 2012). Experimental studies of Sr 2 MnSbO 6 have shown that this compound presents ferroelectric and ferromagnetic behavior in the I4m, I4mm, I4mcm phases, as well as it exhibits high dielectric constant in the cubic phase Fm-3m (Antara, et al, 2011;Foster, et al,1997;Majhi & Varma, 2007). Modifications of this compound recently have been reported by (Bazuev et al, 2021), where is studied the effect of substitutions on the phase formation, structure and magnetic properties of the Sr 2 MnSbO 6 compound.…”