New multiferroics based on EuxSr1−xTiO3 nanotubes and nanowires

Abstract

Using Landau-Ginzburg-Devonshire theory, we have addressed the complex interplay between structural antiferrodistortive order parameter (oxygen octahedron rotations), polarization and magnetization in EuxSr1−xTiO3 nanosystems. We have calculated the phase diagrams of EuxSr1−xTiO3 bulk, nanotubes and nanowires, which include the antiferrodistortive, ferroelectric, ferromagnetic, and antiferromagnetic phases. For EuxSr1−xTiO3 nanosystems, our calculations show the presence of antiferrodistortive-ferroelectric-ferromagnetic phase or the triple phase at low temperatures (≤10 K). The polarization and magnetization values in the triple phase are calculated to be relatively high (∼50 μC/cm2 and ∼0.5 MA/m). Therefore, the strong coupling between structural distortions, polarization, and magnetization suggests the EuxSr1−xTiO3 nanosystems as strong candidates for possible multiferroic applications.

Low-symmetry monoclinic ferroelectric phase stabilized by oxygen octahedra rotations in strained EuxSr1−xTiOMorozovska1, Gu2, Khist3 et al. 2013Phys. Rev. BSelf Cite171191View full textAdd to dashboardCite

“…Gibbs potential coefficients are renormalized by the surface tension [28,38], misfit strains [33] and biquadratic coupling between the structural and polar order parameters [30,. The renormalization details are listed in Appendix A, Suppl.…”

“…Gibbs potential density of Eu x Sr 1-x TiO 3 solid solution as a function of polarization and oxygen octahedra tilt vectors is written as [28]:…”

“…There has been one experimental study on the structural AFD and other physical properties of bulk solid solution Eu x Sr 1-x TiO 3 [27]. Theoretically, possible multiferroic properties of Eu x Sr 1-x TiO 3 nanotubes and nanowires [28] have been predicted using Landau-Ginzburg-Devonshire (LGD) theory. However, in [28], the structural AFD order parameter was considered as a scalar while the true AFD order parameter is an axial vector describing the oxygen octahedral tilt [29].…”

“…Theoretically, possible multiferroic properties of Eu x Sr 1-x TiO 3 nanotubes and nanowires [28] have been predicted using Landau-Ginzburg-Devonshire (LGD) theory. However, in [28], the structural AFD order parameter was considered as a scalar while the true AFD order parameter is an axial vector describing the oxygen octahedral tilt [29]. The vector nature of the AFD order parameter can strongly influence the phase stability, polar and pyroelectric properties of quantum paraelectrics [11,30] at interfaces [31] or in thin film bulk [7,13,32].…”

Novel room temperature multiferroics on the base of single-phase nanostructured perovskites

“…In order to describe the x-composition dependence of the AFM-PM and FM-PM phase transition temperatures we will use the approach [25] based on the percolation theory [26]. We assume a linear dependence of FM ordering on Fe content, x, above the percolation threshold, .…”