TY - JOUR

T1 - Mechanisms of electron transport in BaTiO3 ultrathin epitaxial films in the temperature range 40 K–295 K

AU - Андреева , Наталья Владимировна

AU - Петров, А.А.

AU - Petraru, A.

AU - Петухов, Анатолий Евгеньевич

AU - Рыбкин, Артем Геннадиевич

N1 - Funding Information: The work was funded by the Russian Ministry of Education and Science under Grant No. 16.2873.2017/4.6. The authors are grateful to the resource center ‘Physical Methods of Surface Investigation’ of Research Park of Saint Petersburg State University for UHV AFM measurements (agreement no. S-RC-113/5-DS5).

PY - 2019/2

Y1 - 2019/2

N2 - In this paper, we report the results of experimental study of electron transport mechanisms in ferroelectric BaTiO 3 ultrathin epitaxial films in a broad temperature range. For this purpose ferroelectric tunnel junctions based on STO/LSMO/BTO/Au structures were fabricated with different thicknesses of ferroelectric films (from 3 to 12 nm). Ferroelectric and electrical properties of heterostructures were measured at temperatures ranging from 40 K to 300 K. Based on experimental results, we find that prevailing transport mechanisms in BaTiO 3 epitaxial thin film is determined by the film thickness. Below the certain thickness of the BaTiO 3 film, a dominant contribution in the current through the structure is due to elastic tunneling. Increasing the thickness of the ferroelectric film leads to an impact from inelastic tunneling, mainly due to an interaction with traps caused by cation and anion vacancies in oxide sub-lattices. We suppose that the specificity of transport mechanisms in BaTiO 3 ultrathin films is defined by the ratio of film thickness and the mean free path of injected electrons, along with repolarization processes synchronized with the ferroelectric coercive field. The latter point has been confirmed by the results of experimental study in a broad temperature range.

AB - In this paper, we report the results of experimental study of electron transport mechanisms in ferroelectric BaTiO 3 ultrathin epitaxial films in a broad temperature range. For this purpose ferroelectric tunnel junctions based on STO/LSMO/BTO/Au structures were fabricated with different thicknesses of ferroelectric films (from 3 to 12 nm). Ferroelectric and electrical properties of heterostructures were measured at temperatures ranging from 40 K to 300 K. Based on experimental results, we find that prevailing transport mechanisms in BaTiO 3 epitaxial thin film is determined by the film thickness. Below the certain thickness of the BaTiO 3 film, a dominant contribution in the current through the structure is due to elastic tunneling. Increasing the thickness of the ferroelectric film leads to an impact from inelastic tunneling, mainly due to an interaction with traps caused by cation and anion vacancies in oxide sub-lattices. We suppose that the specificity of transport mechanisms in BaTiO 3 ultrathin films is defined by the ratio of film thickness and the mean free path of injected electrons, along with repolarization processes synchronized with the ferroelectric coercive field. The latter point has been confirmed by the results of experimental study in a broad temperature range.

KW - electron transport mechanisms

KW - ferroelectric tunnel junction

KW - low temperature

KW - FERROELECTRIC TUNNEL-JUNCTIONS

UR - http://www.scopus.com/inward/record.url?scp=85058064871&partnerID=8YFLogxK

UR - http://stacks.iop.org/2053-1591/6/i=2/a=026427?key=crossref.8c5ae42ba3352189a5382912a03c358d

UR - http://www.mendeley.com/research/mechanisms-electron-transport-batio-sub3sub-ultrathin-epitaxial-films-temperature-range-40-k295-k

U2 - 10.1088/2053-1591/aaf24f

DO - 10.1088/2053-1591/aaf24f

M3 - Article

VL - 6

JO - Materials Research Express

JF - Materials Research Express

SN - 2053-1591

IS - 2

M1 - 026427

ER -