SEMINAIRE LMGP - 09/07/2024 - Vijaya Shanthi PAUL RAJ

"Solution growth of functional crystals: towards the identification of defects formation and growth mechanisms"

Vijaya Shanthi PAUL RAJ ^(1)*

⁽¹⁾Post- doctoral researcher

*SIMaP, Institut Neel, CNRS, University of Grenoble Alpes

LMGP, Grenoble-INP, CNRS, Grenoble, France

Thanks to my Ph.D. supervisors Dr. Matias Velazquez   and Dr. Alexandra Pena

Abstract 
The growth mechanism study of two functional single crystals grown from solution, Herbertsmithite (HS) (ZnxCu4-x(OH)6Cl2) and Germanium oxide (GeO2) have been investigated in order to determine the growth conditions leading to good quality crystals. ZnCu3(OH)6Cl2, stoichiometric Herbertsmithite crystals, are needed to study the physics of quantum spin liquids and α-GeO2 ones are promising piezoelectric crystals that could be used at high temperature conditions and as nonlinear optical crystals in optical parametric devices. During this work HS crystals were grown and characterized (LIBS, synchrotron µ-Laue combined with µ-XRF) to determine their chemical composition, their structure, and the surface topography towards the identification formation mechanism. On the other hand, α-GeO2 crystals are grown by top-seeded solution growth-slow cooling (TSSG-SC) in the ternary system by using seeds oriented along [001] it has been observed the presence of optical twins. In order to understand the origin of the twin formation mechanism, a thorough analysis of their propagation—from the start to the finish of the development process—as well as the orientation of the twin boundaries have been conducted using X-ray topography in this work.

Short Bio/CV
I am currently a post-doctoral researcher at LMGP, Funsurf team working in “developing the SALD processes with new precursors”. In 2023, I worked as a post-doctoral fellow on the quantum spin liquids in kagome materials project at the Institut Laue Langevein (ILL), Grenoble. I graduated from the University of Grenoble Alpes in 2023 with a Ph.D. During my Ph.D studies at SIMaP and Institut Neel, I investigated growth generation mechanisms in quantum spin liquid crystals and investigated optical twins using piezoelectric crystals. I also worked as a research associate at International Nanotechnology Laboratory, Braga Portugal in 2019. I studied Physics in India for my B.Sc. and M.Sc. degrees.