Extreme dielectric non-linearities at the convergence point in Ba1-xCaxTi1-xZrxO3 thin films

JOURNAL OF ALLOYS AND COMPOUNDS

卷:747

Article

Simon, Q.^1,2  Daumont, C. J. M.²  Payan, S.¹  Gardes, P.³  Poveda, P.³  Wolfman, J.²  Maglione, M.¹ 

[1] Univ Bordeaux, UPR ICMCB CNRS 9048, Inst Chim Mat Condensee Bordeaux, F-33608 Pessac, France

[2] Univ Tours, UMR7347, Lab GREMAN, CNRS, F-37200 Tours, France

[3] STMicroelectronics, 10 Rue Thales Milet, F-37071 Tours, France

关键词: BCTZ;    Thin film;    Dielectric;    Tunable capacitors;    Sputtering;    Lead-free relaxor;   

DOI  :  10.1016/j.jallcom.2018.03.010

来源: Elsevier

【 摘 要 】

The dielectric properties of Ba1-xCaxTi1-xZrxO3 (BCTZ) thin films are explored by varying x from 0 to 0.18 through an RF magnetron co-sputtering process. Thin films are analyzed by Rutherford Backscattering Spectroscopy, X-Ray Diffraction and dielectric measurements on parallel plate capacitors as a function of temperature (from 100 to 420 K), frequency (from 100 Hz to 1 MHz) and static electric field (from 0 to 250 kV cm(-1)). The evolutions of their dielectric properties with composition are systematically compared to bulk ceramic counterparts. In both cases, a continuous crossover from classical-to-relaxor ferroelectric behavior along with a decrease of the temperature of the permittivity maximum are observed as x increases. Besides, a phase convergence region (PCR) between cubic, tetragonal, orthorhombic and rhombohedral symmetries is evidenced for compositions close to x = 0.12. This is the first time that such a PCR is observed in thin films. At this point in the phase diagram, all of the dielectric parameters undergo specific variations. In particular, the enhanced permittivity dependence to external electric field for these Ca and Zr contents is attributed to an emerging relaxor behavior together with its vicinity of the PCR. These results make BCTZ thin films potential candidates to achieve electrically tunable devices. (C) 2018 Elsevier B.V. All rights reserved.

【 授权许可】

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