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Title: Decoupling Mesoscale Functional Response in PLZT across the Ferroelectric–Relaxor Phase Transition with Contact Kelvin Probe Force Microscopy and Machine Learning

Relaxor ferroelectrics exhibit a range of interesting material behavior, including high electromechanical response, polarization rotations, as well as temperature and electric field-driven phase transitions. The origin of this unusual functional behavior remains elusive due to limited knowledge on polarization dynamics at the nanoscale. Piezoresponse force microscopy and associated switching spectroscopy provide access to local electromechanical properties on the micro- and nanoscale, which can help to address some of these gaps in our knowledge. However, these techniques are inherently prone to artefacts caused by signal contributions emanating from electrostatic interactions between tip and sample. Understanding functional behavior of complex, disordered systems like relaxor materials with unknown electromechanical properties therefore requires a technique that allows distinguishing between electromechanical and electrostatic response. Here, contact Kelvin probe force microscopy (cKPFM) is used to gain insight into the evolution of local electromechanical and capacitive properties of a representative relaxor material lead lanthanum zirconate across the phase transition from a ferroelectric to relaxor state. The obtained multidimensional data set was processed using an unsupervised machine learning algorithm to detect variations in functional response across the probed area and temperature range. Further analysis showed the formation of two separate cKPFM response bands below 50 °C, providing evidencemore » for polarization switching. At higher temperatures only one band is observed, indicating an electrostatic origin of the measured response. In addition, the junction potential difference, which was extracted from the cKPFM data, becomes independent of the temperature in the relaxor state. As a result, the combination of this multidimensional voltage spectroscopy technique and machine learning allows to identify the origin of the measured functional response and to decouple ferroelectric from electrostatic phenomena necessary to understand the functional behavior of complex, disordered systems like relaxor materials.« less
Authors:
ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [2] ;  [2] ; ORCiD logo [2] ;  [3] ; ORCiD logo [2] ; ORCiD logo [4] ; ORCiD logo [2] ; ORCiD logo [5]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. College Dublin, Dublin (Ireland)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Ural Federal Univ., Ekaterinburg (Russia)
  4. Ural Federal Univ., Ekaterinburg (Russia); CICECO - Aveiro Institute of Materials, Aveiro (Portugal)
  5. Univ. College Dublin, Dublin (Ireland)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
ACS Applied Materials and Interfaces
Additional Journal Information:
Journal Volume: 10; Journal Issue: 49; Journal ID: ISSN 1944-8244
Publisher:
American Chemical Society (ACS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; contact Kelvin probe force microscopy; k-means clustering; lead lanthanum zirconium titanate; machine learning; phase transition; piezoresponse force microscopy; relaxor ferroelectric
OSTI Identifier:
1486952

Neumayer, Sabine M., Collins, Liam F., Vasudevan, Rama K., Smith, Christopher R., Somnath, Suhas, Shur, Vladimir Ya., Jesse, Stephen, Kholkin, Andrei L., Kalinin, Sergei V., and Rodriguez, Brian J.. Decoupling Mesoscale Functional Response in PLZT across the Ferroelectric–Relaxor Phase Transition with Contact Kelvin Probe Force Microscopy and Machine Learning. United States: N. p., Web. doi:10.1021/acsami.8b15872.
Neumayer, Sabine M., Collins, Liam F., Vasudevan, Rama K., Smith, Christopher R., Somnath, Suhas, Shur, Vladimir Ya., Jesse, Stephen, Kholkin, Andrei L., Kalinin, Sergei V., & Rodriguez, Brian J.. Decoupling Mesoscale Functional Response in PLZT across the Ferroelectric–Relaxor Phase Transition with Contact Kelvin Probe Force Microscopy and Machine Learning. United States. doi:10.1021/acsami.8b15872.
Neumayer, Sabine M., Collins, Liam F., Vasudevan, Rama K., Smith, Christopher R., Somnath, Suhas, Shur, Vladimir Ya., Jesse, Stephen, Kholkin, Andrei L., Kalinin, Sergei V., and Rodriguez, Brian J.. 2018. "Decoupling Mesoscale Functional Response in PLZT across the Ferroelectric–Relaxor Phase Transition with Contact Kelvin Probe Force Microscopy and Machine Learning". United States. doi:10.1021/acsami.8b15872.
@article{osti_1486952,
title = {Decoupling Mesoscale Functional Response in PLZT across the Ferroelectric–Relaxor Phase Transition with Contact Kelvin Probe Force Microscopy and Machine Learning},
author = {Neumayer, Sabine M. and Collins, Liam F. and Vasudevan, Rama K. and Smith, Christopher R. and Somnath, Suhas and Shur, Vladimir Ya. and Jesse, Stephen and Kholkin, Andrei L. and Kalinin, Sergei V. and Rodriguez, Brian J.},
abstractNote = {Relaxor ferroelectrics exhibit a range of interesting material behavior, including high electromechanical response, polarization rotations, as well as temperature and electric field-driven phase transitions. The origin of this unusual functional behavior remains elusive due to limited knowledge on polarization dynamics at the nanoscale. Piezoresponse force microscopy and associated switching spectroscopy provide access to local electromechanical properties on the micro- and nanoscale, which can help to address some of these gaps in our knowledge. However, these techniques are inherently prone to artefacts caused by signal contributions emanating from electrostatic interactions between tip and sample. Understanding functional behavior of complex, disordered systems like relaxor materials with unknown electromechanical properties therefore requires a technique that allows distinguishing between electromechanical and electrostatic response. Here, contact Kelvin probe force microscopy (cKPFM) is used to gain insight into the evolution of local electromechanical and capacitive properties of a representative relaxor material lead lanthanum zirconate across the phase transition from a ferroelectric to relaxor state. The obtained multidimensional data set was processed using an unsupervised machine learning algorithm to detect variations in functional response across the probed area and temperature range. Further analysis showed the formation of two separate cKPFM response bands below 50 °C, providing evidence for polarization switching. At higher temperatures only one band is observed, indicating an electrostatic origin of the measured response. In addition, the junction potential difference, which was extracted from the cKPFM data, becomes independent of the temperature in the relaxor state. As a result, the combination of this multidimensional voltage spectroscopy technique and machine learning allows to identify the origin of the measured functional response and to decouple ferroelectric from electrostatic phenomena necessary to understand the functional behavior of complex, disordered systems like relaxor materials.},
doi = {10.1021/acsami.8b15872},
journal = {ACS Applied Materials and Interfaces},
number = 49,
volume = 10,
place = {United States},
year = {2018},
month = {11}
}