Effect of strain on ferroelectric field effect in strongly correlated oxide Sm_0.5Nd_0.5NiO₃

Authors

Le Zhang, University of Nebraska-LincolnFollow
Chen, University of Nebraska-LincolnFollow
H. J. Gardner, University of Nebraska-Lincoln
Mark A. Koten, University of Nebraska-LincolnFollow
Jeffrey E. Shield, University of Nebraska-LincolnFollow
Xia Hong, University of Nebraska–LincolnFollow

Date of this Version

2015

Citation

APPLIED PHYSICS LETTERS 107, 152906 (2015)

Comments

copyright (c) 2015 AIP Publishing LLC. Used by permission.

Abstract

We report the effect of epitaxial strain on the magnitude and retention of the ferroelectric field effect in high quality PbZr_0.3Ti_0.7O₃ (PZT)/3.8–4.3 nm Sm_0.5Nd_0.5NiO₃ (SNNO) heterostructures grown on (001) LaAlO₃ (LAO) and SrTiO₃ (STO) substrates. For SNNO on LAO, which exhibits a first-order metal-insulator transition (MIT), switching the polarization of PZT induces a 10K shift in the transition temperature TMI, with a maximum resistance change between the on and off states of ΔR = R_on ~75%. In sharp contrast, only up to 5% resistance change has been induced in SNNO on STO, where the MIT is second-order, with the modulation of T_MI negligibly small. We also observe thermally activated retention of the off state resistance Roff in both systems, with the activation energy of 22 meV (28 meV) for devices on LAO (STO). The time dynamics and thermal response of the field effect instability points to phonon-assisted interfacial trapping of charged mobile defects, which are attributed to strain induced oxygen vacancies. At room temperature, Roff stabilizes at ~55% and ~19% of the initial switching levels for SNNO on LAO and STO, respectively, reflecting the significantly different oxygen vacancy densities in these two systems. Our results reveal the critical role of strain in engineering and modeling the complex oxide composite structures for nanoelectronic and spintronic applications.