Thermally controlled structural strain reduction in core shell magnetoelectric nanocomposite

Abstract

In this research, we have presented detailed studies of the effect of temperature-controlled hydrothermal fabrication techniques on the morphology and structural strain in magnetoelectric core-shell nanocomposite having magnetic CoFe₂O₄ core coated with a piezoelectric BaTiO₃ shell. We have presented the effect of controlled cooling rate during annealing process of synthesis on the structural integrity and structural strain of the core-shell hetero-nanostructure. Using temperature controlled hydrothermal method, it has been observed that controlling the cooling rate to 20 °C/min while annealing process leads to low structural strain on the deposited BaTiO₃ shell. This also leads to high structural integrity of the fabricated heterostructure nanocomposite. To measure the strain distribution in the coated shell, geometric phase analysis was performed on the high-resolution transmission electron microscopic image of the fabricated core-shell nanostructure. Semi quantitative Energy-dispersive X-ray spectroscopy line scan elemental mapping have confirmed the elemental distribution throughout the nanostructure and formation of the core–shell structure. Moreover, through the geometric phase analysis, the core and the shell can be distinctively visualized which confirms the homogeneity of the coating of single crystalline BaTiO₃ shell on the CoFe₂O₄ core.

Keywords:

• Core shell nanostructure
• geometric phase analysis
• high resolution transmission electron microscopy
• magnetoelectric nanocomposite
• semi-quantitative energy dispersive X-ray spectroscopy

Additional information

Funding

Author S.B. acknowledge the support by Science Research and Engineering Board (grant no. CRG/2021/003525), and A.S.B and R.G. acknowledge the support by National Science foundation (grant no. NSF 1002380), US Department of Defense (grant no. W911NF-12-1-0082).