Research

Research overview:

Keywords: |Ferroelectrics ceramics and thin films for energy storage applications |Magnetoelectric layered and bulk composite |Piezoelectric/pyroelectric ceramics and composites for actuation | Pulsed laser deposition|

Moreover, our research interests are driven by current experimental observations that challenge the standard paradigms of ferroelectric, piezoelectric and magnetoelectric oxides in bulk and thin film geometry. Currently our focus on investigating the fundamental and multifunctional aspects of ferroelectric oxides and their interface related phenomena pertaining to multiferroics, electrocaloric, energy storage, triboelectric and sensor applications.

I- Some research highlights of postdoctoral research works at IIT Bombay

1. Structural, dielectric and ferroelectric studies of un-doped and co-doped barium titanate thin films:

Fig. 1 Schematic representation of Monolayers of BTO and doped BTO on Pt/Ti/Si/SiO2 (100) Substrate

Fig. 2 Schematic representation of Monolayers of BTO and doped BTO on SrTiO3 (STO) Substrate

The XRD pattern exhibits a combination of primary phases of the deposited film(s) and the substrate. Interestingly, a significant amount of bulk peaks are retained in the films, with reduced relative intensity.
The cross-sectional Scanning Electron Microscopy of the deposited thin films confirm that the deposited films exhibit sequential heterostructure growth.
A thick and relatively uniform growth is observed when we use LSCO as a seed layer.
A well-saturated ferroelectric hysteresis of high saturation polarization was observed in both the films.

Key findings of above work:

2. Structural and multiferroic behavior of BaTiO3/CoFe2O4 based multilayers:

Fig. 1 Schematic representation of Bilayers of BTO and CFO on Pt/Ti/Si/SiO2 (100) Substrate

Fig. 2 Schematic representation of Bilayers of BCST and CFO on Pt/Ti/Si/SiO2 (100) Substrate

Fig. 3 Schematic representation of Trilayers of BTO and CFO on Pt/Ti/Si/SiO2 (100) Substrate

Fig. 4 Schematic representation of Trilayers of BCSTO and CFO on Pt/Ti/Si/SiO2 (100) Substrate

Key findings of above work:

X-ray diffraction pattern

Dielectric constant of Bilayers/Trilayers

Raman Spectra

Lead free multiferroic bilayers/trilayers has been deposited on Pt/Ti/SiO2/Si (100) substrate by pulsed laser deposition technique.
The structural and phase purity data were acquired using grazing incidence x-ray diffraction (GI-XRD) studies that confirm the growth of polycrystalline heterostructures and the coexistence of both perovskite BTO and spinel CFO phases in heterostructures
The FE-SEM micro graph reveals dense and crack free images that confirms good quality thin films were deposited on subsequent substrate
A high value of real dielectric constant which is about 32450 at 1kHz and room temperature observed in CFO/BTO/CFO trilayers as compared to bilayers CFO/BTO which is nearly 8532 at same conditions

II- Some research highlights of Ph.D. works at Aligarh Muslim University

1. Superior energy storage performance and excellent multiferroic properties of Gd-doped BaTiO3 ceramics

Key findings:

The doping of Gd at the Ti site causes the transformation of the ferroelectric behaviour to the relaxor ceramics, which is important for finding the large energy storage efficiency of the material.
Moreover, the energy discharge density and energy storage efficiency boosted in x=0.02 and x=0.04 nanostructured samples and were found to be 81 and 83%.
The maximum values of the piezoelectric coefficient (d33) are found to be 243 pC/N, 215 pC/N, 154 pC/N and 115 pC/N for the x=0.0 to x=0.06, respectively.

2. Correlative exploration of structural, electrical, magnetic, and magnetoelectric coupling study of lead-free (0-3) type multiferroic composites: A comprehensive Analysis

Key findings:

The composites' multiphase nature is confirmed by the Rietveld refinement analysis.
The magnetic moment and ME coefficient (αME) of the composite sample significantly enhance as the guest CoFe2O4 is added to the bare BaTiO3 system.
The ferroelectricity of composites drops down due to fluctuations in the state of Fe2+/Fe3+ ions that enhance the leakage current of the composite sample.
A notable enhancement in the magnetoelectric coefficient response has been noted due to the connection of the ferroelectric and ferromagnetic phases.