Understanding structure and electronic correlation in ordered systems and implementing it in material engineering for practical applications is one of the thrust areas of research in contemporary material science. Emergence of novel properties on nanostructuring and atomic level manipulation of matter creating new functionalities paved the way for faster devises with multiple controls. Application of these functional materials for the welfare of human beings especially in communications, health, sustainable energy and environmental problems is one of the biggest challenges in front of twentieth century solid state science research. Our group's research is mainly focused on the studies of structural, magnetic and electronic properties of matter.
Magnetic Nanofluids for heat transport applications:
Magnetic nanofluids are colloidal dispersions of magnetic nanoparticles in a base fluid, and they exhibit magnetic as well as fluid properties. The thermal conductivity of a magnetic nanofluid can be tuned with the application of an external magnetic field making them suitable for cooling applications. Our research is focused on understanding ways to improve the thermal conductivity of magnetic nanofluids.
- Arun Dadwal and P. A. Joy, Influence of chain length of long-chain fatty acid surfactant on the thermal conductivity of magnetite nanofluids in a magnetic field, Colloids and Surfaces A: Physicochemical and Engineering Aspects 555, 525 (2018)
- R. Lenin and P. A. Joy, Studies on the role of unsaturation in the fatty acid surfactant molecule on the thermal conductivity of magnetite nanofluids, Journal of Colloids and Interfacial Science 506, 162 (2017)
- R. Lenin and P. A. Joy, Role of base fluid on the thermal conductivity of oleic acid coated magnetite nanofluids, Colloids and Surfaces A: Physicochemical and Engineering Aspects 529, 922 (2017)
- R. Lenin and P. A. Joy, Role of Primary and Secondary Surfactant Layers on the Thermal Conductivity of Lauric Acid Coated Magnetite Nanofluids, J. Physical Chemistry C 120, 11640 (2016)
Magnetic properties of perovskite type multiferroic oxides:
We study the magnetic and structural properties of nanoparticles of room temperature multiferroics like BiFeO3 and on substitution. Substitution induced crossover from spatially modulated spiral spin structure to homogeneous canted spin structure along with origin of magnetic anomalies at low temperature and at morphotropic phase boundary region are interesting area of research in our group.
- B. Manjunath, P. Thakuria,P. A. Joy, Structural, magnetic, dielectric and magnetodielectric properties of Bi1-xCaxFe1-xMnxO3 in the morphotropic phase boundary region, Materials Research Express 4, 016104 (2017)
- P. Thakuria, P.A. Joy, Enhanced magnetic parameters in the morphotropic phase boundary region of nanocrystalline multiferroic Bi1-xLaxFeO3, Solid State Communications, 152 (2012) 1609–1612
- Pankaj Thakuria, P. A. Joy, High room temperature ferromagnetic moment of Ho substituted nanocrystalline BiFeO3 , Appl. Phys. Lett,97 (2010), 162504 -1-4
- S. Vijayanand, M. B. Mahajan, H. S. Potdar, P. A. Joy, Magnetic characteristics of nanocrystalline multiferroic BiFeO3 at low temperatures, Phys. Rev. B,80 (2009), 064423-1-5
Magnetostriction in spinel oxides:
Low cost, stable and durable Magnetostrictive materials are very important for the sensor and actuator applications. Microstructure and processing dependence of magnetostriction of spinel type of oxides like CoFe2O4 is another area research in our group. Recently we reported increased magntotriction and coupling coefficent in sintered CoFe2O4 derived form superparamagnetic nanoparticle.
- P. N. Anantharamaiah and P. A. Joy, Effect of size and site preference of trivalent non-magnetic metal ions (Al3+, Ga3+, In3+) substituted for Fe3+ on the magnetostrictive properties of sintered CoFe2O4, Journal of Physics D:Applied Physics 50, 435005 (2017)
- P. N. Anantharamaiah and P. A. Joy, Tuning of the magnetostrictive properties of cobalt ferrite by forced distribution of substituted divalent metal ions at different crystallographic sites, Journal of Applied Physics 121, 093904 (2017)
- Enhancement in the magnetostriction of sintered cobalt ferrite by making self-composites from nanocrystalline and bulk powders, K. K. Mohaideen and P. A. Joy, ACS Applied Materials & Interfaces 4, 6421 (2012)
- K. Khaja Mohaideen, P. A. Joy, High magnetostriction and coupling coefficient for sintered cobalt ferrite derived from superparamagnetic nanoparticles, Appl. Phys. Lett, 101(2012) , 072405 -1-4
Surface functionalized nanoparticles for biomedical applications:
Surface modified uniform, monodisperse, biocompatible magnetic nanoparticles have proved to be potential candidate for biomedical applications such as targeted drug delivery, magnetic hyperthermia, MRI contrast agent etc. as well as for environmental problems. We are working on surface functionalization of magnetic nanoparticles with different biocompatible surfactanst for different biological applications. We study magnetic properties of functionalized particles at low temperature as well as at room temperature (2K-300K) .
- K. N. Jayaprabha and P. A. Joy, Citrate modified beta-cyclodextrin functionalised magnetite nanoparticles: A biocompatible platform for hydrophobic drug delivery, RSC Advances 5, 22117 (2015)
- V. Sreeja, K. N. Jayaprabha and P. A. Joy, Water dispersible ascorbic acid coated magnetite nanoparticles for contrast enhancement in MRI, Applied Nanoscience 5, 435-441 (2015)
- K. N. Jayaprabha and P. A. Joy, Curcumin encapsulated superparamagnetic iron oxide based nanofluids for possible multifunctional applications, J. Nanofluids 3, 1-7 (2014)
Structural studies using solid state NMR:
We use Solid State NMR Spectroscopy as a technique to understand structure-property correlations in materials, including nanomaterials.
- Bindu Baby, K. K. Dey, T. G. Ajithkumar, P. A. Joy, Identification of the Zn Substitution Sites in La-Zn Substituted SrAl12O19 from 27Al Solid-State NMR Studies, J. Amer. Ceram. Soc. 97(9), 2990-95 (2014)
- K. Harindranath. K. Anusree Viswanath, C. Vinod Chandran, Thomas Brauniger, P.K. Madhu, T.G. Ajithkumar, P. A. Joy, Evidence for the co-existence of distorted tetrahedral and trigonal bipyramidal aluminium sites in SrAl12O19 from 27Al NMR studies, Solid State Commun. 150, 262 (2010)
- V Sreeja, T S Smitha, D Nand, T G Ajithkumar, P A Joy, size dependent coordination behavior and cation distribution in MgAl2O4 nanoparticles from Al-27 solid state NMR studies, J. Phys. Chem. C112, 14737-14744 ( 2008 )
Materials for Energy and Environmental applications:
We are also working on materials for energy conversion and other applications. In these projects we are trying to develop cost effective materials for applications like solar energy conversion, water splitting, supercapacitors, batteries etc.
- K. Govind Raj and P. A. Joy, Role of localized graphitization on the electrical and magnetic properties of activated carbon, Journal of the American Ceramic Society 100, 5151 (2017)
- R. M. Ramsundar, J. Debgupta, V. K. Pillai, and P. A. Joy, Co3O4 nanorods – efficient non-noble metal electrocatalyst for oxygen evolution at neutral pH, Electrocatalysis 6, 331-340 (2015)
- K. Govind Raj, P. A. Joy, Coconut shell based activated carbon-iron oxide magnetic nanocomposite for fast and efficient removal of oil spills, Journal of Environmental Chemical Engineering 3, 2068-75 (2015)
- K. Govind Raj, P. A. Joy, Cross over from 3D variable range hopping to 2D weak localization conduction mechanism in disordered carbon with the extent of graphitization, Physical Chemistry Chemical Physics 17, 16178 (2015)
- S. Vijayanand, R. Kannan, H. S. Potdar, V. K. Pillai, P. A. Joy, Porous Co3O4 nanorods as superior electrode material for supercapacitors and rechargeable Li-ion batteries, Journal of Applied Electrochemistry 43, 995-1003 (2013)
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