Enhanced pyroelectric properties of Bi1−xLaxFeO3 thin films
Abstract
There is growing interest in the study of thin-film pyroelectric materials because of their potential for high performance thermal-energy conversion, thermal sensing, and beyond. Electrothermal susceptibilities, such as pyroelectricity, are known to be enhanced in proximity to polar instabilities, and this is conventionally accomplished by positioning the material close to a temperature-driven ferroelectric-to-paraelectric phase transition. The high Curie temperature (TC) for many ferroelectrics, however, limits the utility of these materials at room-temperature. Here, the nature of pyroelectric response in thin films of the widely studied multiferroic Bi1−xLaxFeO3 (x = 0–0.45) is probed. While BiFeO3 itself has a high TC, lanthanum substitution results in a chemically induced lowering of the ferroelectric-to-paraelectric and structural-phase transition. The effect of isovalent lanthanum substitution on the structural, dielectric, ferroelectric, and pyroelectric response is investigated using reciprocal-space-mapping studies; field-, frequency-, and temperature-dependent electrical measurements; and phase-sensitive pyroelectric measurements, respectively. While BiFeO3 itself has a rather small pyroelectric coefficient at room temperature (∼−40 µC/m2 K), 15% lanthanum substitution results in an enhancement of the pyroelectric coefficient by 100% which is found to arise from a systematic lowering of TC.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 01, 2019
- Source ID
- 10.1063/1.5128413
Entities
People
- Anirban Ghosh
- David Garcia
- Gabriel Velarde
- Lane W Martin
- Lei Zhang
- Ramamoorthy Ramesh
- Shishir Pandya
- Yen-lin Huang
Organizations
- Army Research Office
- Lawrence Berkeley National Laboratory
- National Science Foundation