Ma, Yang-Bin ; Grünebohm, Anna ; Meyer, Kai-Christian ; Albe, Karsten ; Xu, Bai-Xiang (2016)
Positive and negative electrocaloric effect in BaTiO3 in the presence of defect dipoles.
In: Physical Review B, 94 (9)
doi: 10.1103/PhysRevB.94.094113
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
The influence of defect dipoles on the electrocaloric effect (ECE) in acceptor doped BaTiO3 is studied by means of lattice-based Monte-Carlo simulations using a Ginzburg-Landau type effective Hamiltonian. Oxygen vacancy-acceptor associates are described by fixed local dipoles with orientation parallel or antiparallel to the external field. By a combination of canonical and microcanonical simulations the ECE is directly evaluated. Our results reveal that in the case of antiparallel defect dipoles the ECE can be positive or negative depending on the dipole density. Moreover, a transition from a negative to positive ECE can be observed when the external field increases. These transitions are due to the delicate interplay of internal and external fields and are explained by the domain structure evolution and related field-induced entropy changes. The results are in good qualitative agreement to those obtained by molecular dynamics simulations employing an ab initio based effective Hamiltonian. Finally, a modified electrocaloric cycle, which makes use of the negative ECE in the presence of defect dipoles, is proposed to enhance the cooling effect.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2016 |
| Autor(en): | Ma, Yang-Bin ; Grünebohm, Anna ; Meyer, Kai-Christian ; Albe, Karsten ; Xu, Bai-Xiang |
| Art des Eintrags: | Bibliographie |
| Titel: | Positive and negative electrocaloric effect in BaTiO3 in the presence of defect dipoles |
| Sprache: | Englisch |
| Publikationsjahr: | 29 September 2016 |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Physical Review B |
| Jahrgang/Volume einer Zeitschrift: | 94 |
| (Heft-)Nummer: | 9 |
| DOI: | 10.1103/PhysRevB.94.094113 |
| Kurzbeschreibung (Abstract): | The influence of defect dipoles on the electrocaloric effect (ECE) in acceptor doped BaTiO3 is studied by means of lattice-based Monte-Carlo simulations using a Ginzburg-Landau type effective Hamiltonian. Oxygen vacancy-acceptor associates are described by fixed local dipoles with orientation parallel or antiparallel to the external field. By a combination of canonical and microcanonical simulations the ECE is directly evaluated. Our results reveal that in the case of antiparallel defect dipoles the ECE can be positive or negative depending on the dipole density. Moreover, a transition from a negative to positive ECE can be observed when the external field increases. These transitions are due to the delicate interplay of internal and external fields and are explained by the domain structure evolution and related field-induced entropy changes. The results are in good qualitative agreement to those obtained by molecular dynamics simulations employing an ab initio based effective Hamiltonian. Finally, a modified electrocaloric cycle, which makes use of the negative ECE in the presence of defect dipoles, is proposed to enhance the cooling effect. |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Mechanik Funktionaler Materialien 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Materialmodellierung Zentrale Einrichtungen Zentrale Einrichtungen > Hochschulrechenzentrum (HRZ) Zentrale Einrichtungen > Hochschulrechenzentrum (HRZ) > Hochleistungsrechner |
| Hinterlegungsdatum: | 30 Sep 2016 10:54 |
| Letzte Änderung: | 26 Jan 2024 09:21 |
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