Abstract:
Oxides become an important group of quantum materials of interesting fundamental
many body physics due to the presence of strongly correlated electronic and magnetic
states. The hunch for developing new devices using the broad functionalities of Oxides
has given the birth of new technical field called Oxide Electronics. Over past two decades
research in oxide thin fi lms has been boosted due to the invention of new deposition techniques to make ultra thin single crystalline films with novel structure and functionality of
the material that are inaccessible in it's bulk from with the help of reduced dimensionality
and strain engineering with substrates. Designing novel polar and magnetic ordering in
some new strain stabilized engineered oxide thin films as well as heterostructures is going
to be the key focus of this thesis with a strong future perspective in quantum technology
& device science.
A variety of ferroelectric and ferromagnetic transition metal oxides (TMO) have been
thoroughly explored in this thesis in terms of their thin fi lm growth as well as polar and
magnetic properties. Firstly thin fi lm of arti ficial hexagonal phase of perovskite TbMnO3
has been grown and stabilized with the imposed strain of the substrate. The high ferro-
electric transition temperature(Tc = 800 K) of this room temperature ferroelectrics has
been investigated with temperature dependent Transmission Electron Microscopy, Raman
spectroscopy and optical ellipsometry. Secondly thin film of monoclinic double perovskite
Tb2CoMnO6 has been grown and it's detail dielectric and magnetic properties have been
investigated. An interesting and novel ferroelectric relaxor glass phase has been observed
in this ferromagnetic oxide along with a magneto-dielectric coupling (4%) at considerable
high temperature. Third and most importantly a 3d-5d electronic system based perovskite
ferroelectric-magnetic thin fi lm hetero-structure of BaTiO3/SrIrO3 has been grown and
an enhanced magnetic ordering has been observed via interfacial coupling probed with
depth dependent x-ray photoelectron spectroscopy. At the end as an Appendix we have
explored the integration of a new 2 dimensional material Borocarbonitride (BCN) on ox-
ide which is Al2O3. we have extensively studied the room temperature enhancement of
magnetic ordering along with temperature and nitrogen dependent transport crossover in
the thin fi lms.
