Isothermal structural transitions, magnetization and large piezoelectric response in Bi1−xLaxFeO

I. O. Troyanchuk¹,

D. V. Karpinsky

²

,

M. V. Bushinsky³

et al.

Abstract

We report on the discovery of an isothermal structural transition observed in Bi 1−x La x FeO 3 (0.17 x 0.19) ceramics. At room temperature, an initially pure polar rhombohedral phase gradually transforms into a pure antipolar orthorhombic one. The polar phase can be recovered by annealing at T > 300 • C. In accordance with neutron powder diffraction data, an inverse isothermal antipolar-polar transition takes place at T > 300 • C, where the polar phase becomes more stable. The antipolar phase is characterized by a weak ferromagnetic state, whereas the polar phase has been obtained in a mixed antiferromagnet-weak ferromagnet state. The relatively low external pressure induces polar-antipolar transition, but there is no evidence of electric-field-driven antipolar-polar transition. The observed large local piezoelectric response is associated with structural instability of the polar phase, whereas local multistate piezoelectric loops can be related to the domain wall pinning effect.

Unusual Phase Behavior in the Piezoelectric Perovskite System, LixNa1–xNbO3

“…Recent reports in the literature confirm that similar non-diffuse phase transitions occur in other perovskite materials. 24 Using Glazer notation, phase Q has the a -b + a -tilt system, and Na-R3c has the a -a -a -tilt system, as shown in Fig. 3.…”

Structural and magnetic properties of isovalently substituted multiferroic BiFeO3: Insights from Raman spectroscopy

“…15 A similar transition, albeit more complicated, is reported in the intensely studied Bi 1−x La x FeO 3 series. 5,[16][17][18][19] Here the similar ionic radii between Bi and La makes it possible to stabilize several intermediate structures before the final P nma structure is reached at 50% La content. 16 XRD and electron diffraction (ED) data indicated a stabilized R3c structure up to 20% La content where a transition towards a P nma structure of the GdFeO 3 type occurred.…”

Interlayer strain effects on the structural behavior of BiFeO3/LaFeO3 superlattices

“…It is important to mention that the STO buffer layer is fully relaxed (aMgO= 4.213 Å>> aSTO= 3.905 Å). /(LaFeO3)x superlattices 9 , in rare-earth substituted BiFeO3 2,3,12 and in the Bi1-xLaxFeO3 solid solution 15,16 . From the comparison of the FFT we can correlate antiferroelectric…”

“…These Raman spectra closely resemble the Raman spectra obtained near the MPB for Bi1-xLaxFeO3 solid solution (0.2≤x≤0.5) by Bielecki et al 16 . For these 15 compositions, the authors suggest the existence of a PbZrO3 antiferroelectric-like state. It is believed that this antiferroelectric distorsion acts like a structural bridge between rhombohedral R3c and orthorhombic Pnma phases.…”

“…Thus in our SLs, the peculiar domains observed in BFO layers is identified as a PbZrO3-like structure. At present, in literature the PbZrO3-like structure detected at the MPB for Bi1-xLaxFeO3 solid solutions is the subject of many discussions regarding its symmetry 12,15,17 . This peculiar structure are also discussed for Bi1-xNdxFeO3 system 18 and NaNbO3 19,20 .…”