Back to Search
Start Over
Incommensurate-commensurate transition in the geometric ferroelectric LaTaO4
- Publication Year :
- 2020
-
Abstract
- Funding: UK Engineering and Physical Sciences Research Council (Grant Number(s): EP/P022637/1, EP/K503162/1), Science and Technology Facilities Council (Grant Number(s): RB1820307), China Scholarship Council (CN). The layered perovskite LaTaO4 has been synthesized to be stable in both (polar) orthorhombic and (nonpolar) monoclinic polymorphs at ambient conditions. Although the structural transition between monoclinic and orthorhombic phases has been well established, there is some controversy regarding a further, unidentified transition around 500 K. Here this is identified as an incommensurate–commensurate first‐order transition between incommensurate Cmc21(α00)0s0 and commensurate Cmc21 orthorhombic phases. Transmission electron microscopy indicates partially ordered stacking of different structural units in a, identifying the local cause for the modulation, whereas variable temperature powder neutron diffraction has shown the overall macroscopic modulation vector, q ≈ (0.456, 0, 0)—roughly a 2.2 × expansion in a, corresponding to an approximate 11a commensurate superunit cell dimension. The modulation shows a continuous temperature dependence until transitioning to the basic (commensurate) cell at TIC‐C. Doping the interlayer La sites with smaller Nd cations stabilizes the incommensuration to higher temperature, suggesting the modulation is geometrically driven at the A site. Publisher PDF
- Subjects :
- Materials science
TK
Ferroics
DAS
02 engineering and technology
Structure-property relationships
010402 general chemistry
021001 nanoscience & nanotechnology
Condensed Matter Physics
QD Chemistry
01 natural sciences
Engineering physics
Ferroelectricity
Engineering and Physical Sciences
0104 chemical sciences
Electronic, Optical and Magnetic Materials
TK Electrical engineering. Electronics Nuclear engineering
Biomaterials
Scholarship
Research council
Electrochemistry
Dielectrics
QD
0210 nano-technology
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....270728ff1dcc018c97d0bd0774c0a512