Role of d electrons in multifunctional materials

Title : Role of d electrons in multifunctional materials

Abstract:

Multifunctional materials are of today’s quest. A class of multifunctional materials display simultaneous ordering in different dimensions like magnetism, polarization etc. They are more known as multiferroics. Quite a significant number of them are based on perovskite structures having a transition metal ion in the body centre. The electronic configuration of this central transition element play a key role in the behavior of those multiferroics. For example, those with d0 configuration display ferroelectricity while those with dn (where n is non zero) generally display magnetic behavior. The d0 configuration leads to distortion of metal-oxygen bond in these perovskites and breaking of special inversion symmetry causing a local dipole moment and ferroelectricity. Often this distortion in metal-oxygen bond is caused by lone pair of electrons of non transitional cations in the corners of the perovskite structure.BiFeO3 (BFO) is a shining example of this kind of distortion, where the central ion Fe(III) causes magnetism but Bi(III) ions in the corner cause the polarization leading to the multiferroicity in BFO displaying both ferroelectric and antiferromagntic ordering. The symmetry breaking manifests in different kinds of ordering. Moreover, the variable valency of the central transition metal ion with d electrons manifests in redox behavior in these materials leading to various uses. We have specific capacitance rendering these materials useful in green energy storage materials. Moreover these redox behavior of these transition metal ion also leads to antimicrobial behavior in BFO. 

Audience Take Away: 

• The audience can have an understanding of the role of d electrons with which they can think of developing many other multifunctional materials
• To understand properly the mechanism of the process
• Yes, they can use to enlight other students or researchers
• There will be benefits of proper understanding the basics of multifunctional materials in different dimensions. Moreover, multiferroic materials containing d electrons can be developed with different uses

Biography:

Dr. Sujit Kumar Bandyopadhyay, Emeritus Fellow, Meghnad Saha Institute of Technology (from 2017 to 2020) and Institute of Engineering and Management (2020-2021). Ex-Head, Material Science Studies Division, Scientific Officer (H)⁺ and Professor, Homi Bhabha National Institute, Variable Energy Cyclotron Centre (VECC), Dept. of Atomic Energy, Govt. of India. (Retired on Superannuation on 30^th September, 2015). Academic and Professional Background: 1978: Joined Chemical Engg. Division, Bhabha Atomic Research Centre as Scientific Officer. 1982: Joined Variable Energy Cyclotrn Centre, as Scientific Officer. 1998: PhD (Physics) from Jadavpur University. Title of Thesis: "Charged Particle Irradiation Studies on Copper Oxide Superconductors". Post Doctoral fellow: Atomic Institute of Austrian Universities, Vienna, 2000, in the field of Magnetisation studies of neutron irradiated HTSC superconductor single crystals. Professor, Homi Bhabha National Institute, deemed University since 2009. Awards: 1. National Science Talent Search (NSTS) Scholarship, 1971. 2. National Scholarship, Government of India, 1971. 3. A P J Abdul Kalam award for utstanding research. Current Areas of Interest: Multifunctional Materials in Nanostructured form and their application as energy storage material. A). Capacitance Studies on Multifunctional nanostructured materials with respect to their application as energy storage device. Publications: Journal papers & Articles in books: 86. Proceedings in National & International Conferences: 66. Author of e-book Charged Particle Irradiation Studies on Bismuth Based High Temperature Superconductors & MgB2; A Comparative Survey. Regular Reviewer in Science Direct journals like Materials Chemistry & Physics, Jl. Of alloys and compounds and Jl. Of Solid State Chemistry. Reviewer of Ph.D. Theses of various universities like Burdwan University, Tejpur University etc. Registered Guide for a) Jadavpur University and b) HBNI.