Materials Science and Engineering
Ahmad Safari’s research interests include the structure-property relationships in ferroelectric, dielectric and piezoelectric materials in the form of thin films, bulk ceramics & ceramic –polymer composites for sensor and actuator applications, solid free form fabrication of advance functional materials. Recent work at Dr. Safari’s Glenn Howatt Electroceramic Laboratory has emphasized the development of Pb-Free piezoelectric ceramics and epitaxial thin films in KNN and BNT based compositions. The group works to probe the fundamental mechanisms and processing parameters that control the magnitude of the achievable properties. It was demonstrated that Mn addition to KNN-LT-LS target resulted in a significant suppression of leakage current and enhancement of polarization saturation in epitaxial thin films. The interest in novel actuator development to amplify displacement response extended to monolithic multimaterial electrostrictive-piezoelectric bi-layer composite. We have demonstrated that monolithic composite can be utilized in Cymbal and unimorph design to achieve very high displacement. Micropen direct writing has been utilized to develop thick films for energy and high frequency transducer applications. The group is beginning to work in Multiferroic thin films by PLD method.
Professor Safari's teaching responsibilities during the 2021-2022 school year are:
- Crystal Chemical & Structure, 14:635:205
- Senior MSE Lab, 14:635:402
- Senior MSE Lab, 14:635:401
- Advanced Electronic Ceramics (Graduate), 16:635:509
Principal Fields of Interest
Structural-property relationship in ferroelectric and piezoelectric materials, Pb- based and Pb-Free piezoelectrics ceramics and composites for transducers and sensors applications, ferroelectric and piezoelectric thin films, and 3-D printing of novel design of advanced functional piezoelectric ceramics.
- E. Taghaddos, M. Hejazi, A. Safari, “Lead-free piezoelectric materials and ultrasonic transducers for medical imaging; A review”, Journal of Advanced Dielectrics, Vol.5, No. 2, (2015).
- E. Taghaddos, M. Hejazi, A. Safari, "Electromechnaicl Properties of Acceptor Doped Pb-Free Piezoelectric ceramics", Journal of American Ceramic Society, Vol 97, (2014).
- M. Hejazi, E. Taghaddos, E. Gurdal, K. Uchino, A. Safari, "High Power performance of acceptor doped Bismuth Sodium Titanate Ceramics", Journal of American Ceramic Society, 97, 10, (2013).
- A. Safari, M. Hejazi, "Lead-Free KNN based Piezoelectric Materials", in Lead-Free Piezoelectrics Edited by S. Priya and S. Nahm; Springer, NY (2012) 139-176.
- M Abazari and A. Safari, Leakage current behavior in KNN-LT-LS thin films prepared by PLD, APL, 97, 262902, 2010.
- P. Ngernchuklin and A. Safari, Bilayer Piezoelectric/Electrostrictive (P/E) Dome Unimorph”, IEEE Transactions of Ultrasonic Ferroelectric and Frequency Control, vol. 56, No. 12, pp. 2744-49, 2009
- N. M. Hagh, B. Jadidian, A. Safari, Lead Free Piezoelectric Ceramic Transducers in the KNN-Solid Solution System, IEEE-UFFC Transaction, vol. 55, no.1, pp. 214-224, 2008.
- A. Safari and E. K. Akdogan, Piezoelectric and Acoustic Materials for Transducer Applications, edited, 495 page, Springer, September 2008.
- J. J. Sun, A. K. Akdogan, M. Vittadello, Lisa Klien, and A. Safari, Characterization and Optical Properties of Sol-Gel Processed PMMA/SiO2 Hybrid Monoliths, Journal of Non-Crystalline Solids, Vol. 353/29, pp. 2807 - 2812, 2007.
- E. K. Akdogan, A. Safari, “Thermodynamic theory of intrinsic finite size effects in PbTiO3 nanocrystals; PART I: Nanoparticle size-dependent tetragonal phase stability” Journal of Applied Physics, JAP 101, 064114, 2007.
- A. Safari, M. Allahverdi, and E. K. Akdogan, “Solid Freeform Fabrication of Piezoelectric Sensors and Actuators, Frontiers in Ferroelectricity, Edited by S. Lang and H. Chan, Springer, PP 177-199, 2006.