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Dr. Dinesh kumar

Research Scientist

Current Research Interest:

  1. Ferroelectric materials
  2. Magnetoelectric composites
  3. Energy harvesting devices
  4. Structural health monitoring devices
  5. EMI shielding materials

Dr. Dinesh kumar completed his Ph.D. from the Indian Institute of Technology Madras in ferroelectric and magnetoelectric materials for multifunctional device applications. At VT India, his research work is focused on designing ferroelectric and magnetoelectric materials with enhanced properties for multifunctional device applications. Currently, he is working on developing high-performance magnetoelectric materials for energy harvesting and structural health monitoring applications. He developed a fully automatic experimental setup to characterize magnetoelectric composite materials in direct and converse mode under resonance and off-resonance condition. He also collaborated with other research groups in the characterization of graphene-polymer composite for electromagnetic shielding (EMI) application.

Google Scholar linkhttps://scholar.google.com/citations?user=WCnJ9LUAAAAJ&hl=en

Research

Magnetoelectrics (ME) are class of multifunctional materials with the coexistence of ferroelectric and magnetic ordering. Due to the coupling of these orders parameters the ME materials allow the manipulation of its magnetization by the application of electric field and vice versa. Most of the high-performance ME materials are two phase composites with magnetic and piezoelectric components. ME coupling allows these composites to sense a magnetic disturbance and its conversion to an electrical signal. Similarly, piezoelectric component of composite can convert vibrations to an electric signal as well. The two phenomena make ME composites are of technological importance and are useful as energy harvester, magnetic field sensor, voltage controlled magnetic switches and gyrators etc.

Large converse magnetoelectric effect

A new magnetoelectric bilayer composite Sm-doped Pb(Mg1/3Nb2/3)-PbTiO3/NiFe2O4 was developed which exhibits a converse magnetoelectric(CME) coefficient of 0.34 G.cm/V. This value is at least an order of magnitude higher than any previously reported CME coefficient for polycrystalline ferrite-based laminate composites. The large CME coefficient is attributed to the high transverse piezoelectric coefficient (d31 ~ -421 pC/N) of the piezoelectric phase. The laminate composite exhibits current to voltage conversion performance of 14 mA/V at the resonance frequency. The performance characteristics as a magnetic switch show that the bi-stable states separated by 25 G can be realized through an AC signal of 5V.