Research Interests of the Condensed Matter Group


The research activities of the Condensed Matter Physics group are centered around the synthesis and characterization of various intermetallic compounds, alloys and transition metal based oxide materials.

We perform powder x-ray diffraction and structural refinement for the confirmation of phase purity. Our group is equipped with various measurement facilities consisting of

  • Magnetic Property Measurement System(MPMS) SQUID Magnetometer (Quantum Design, USA),
  • Cryogen free 15 Tesla system for magnetic, resistivity and dielectric measurements (Cryogenic Ltd., UK),
  • Mossbauer Spectrometer
  • X-Ray Diffractometer.
    • We measure the magnetization of materials using the MPMS SQUID Magnetometer and Cryogen free 15 T VSM (Cryogenic Ltd. UK). We also measure electrical and magneto-transport properties of materials using Cryogen free 15 Telsa system (Cryogenic Ltd. UK) . Dielectric properties of materials are measured using using a LCR meter connected with Cryogen free 15 Telsa system (Cryogenic Ltd. UK).

    Currently, we are in process of growing the single crystals of various intermetallic compounds, alloys and oxide materials for the study of various anisotropic physical properties.

    Some of the current research activities of our group are the following:



    Magnetic and Electrical Properties of Some Novel Transition Metal Based Oxides:
    TMOs having low-D magnetic nature have gotten much attention due to some fascinating properties such as spin-liquids, quantum criticality, magnetodielectric coupling, colossal magnetoresistance and many more. Among all MV2O6(where M=Mn, Cu, Co) family of compounds having quasi 1-D magnetic system have been studied.

    MnV2O6 crystallizes in monoclinic structure and CuV2O6 crystallizes in triclinic structure. We have tried to blend in the interesting properties of CuV2O6 and MnV2O6 in a single compound by doping Cu in Mn site of MnV2O6. We have prepared pure and doped Mn1-xCuxV2O6 (x=0,0.125,0.25) samples by standard solid state reaction technique using Mn(CH3COO)2.4H2O, CuO and V2O5 with purity ≥99.9%.

    Magnetic measurements were done using a commercial vibrating sample magnetometer from Cryogenic Limited, UK (cryogen-free system) in the presence of 0-15T of external magnetic field(H). Doping of Cu in Mn site of MnV2O6 results in decrease of lattice parameters along a and c axis of the sample leaving b-axis unaltered. Increasing Curie tail has been observed with the increase in Cu doping concentration because of breaking infinite magnetic chains, which runs parallel to the b-axis, breaks with Cu doping. Also, orbital moment contribution in total moment of the sample has been observed to increase with increasing Cu doping.

    Variation of magnetization as a function of external magnetic field at 5K for all the samples. [Ref. Khamaru et al. JMMM 2019]



    Magnetic behaviour of some manganese-based alloys having first order structural transition

    Magnetic equiatomic alloys (MEAs) of general formula MM′X(M,M′=transition metal, X = Ge, Si, Sn, etc.) are a new class of shape memory alloys exhibiting intriguing functional properties such as magnetocaloric effectx (MCE), magnetoresistance(MR), exchange bias effect(EBE) etc.

    Among MEAs, MnNiGe is one such well-studied material that undergoes martensite phase transition(MPT) from high temperature hexagonal Ni2In-type structure (space group P63/mmc) to low-temperature orthorhombic TiNiSi-type structure (space group Pnma) at 470 K during cooling. Both martensite (low temperature phase) and austenite (high temperature phase) phases in stoichiometric MnNiGe alloy are paramagnetic (PM) in nature around MPT. On further cooling, it orders antiferromagnetically below 346 K.

    To enhance its functionality and make it usable at room temperature application, several doping studies have been performed such as

    • doping smaller/ larger size atoms in Mn or Ni site (positive/negative chemical pressure),
    • doping larger size atoms in Ge site (negative chemical pressure)
    • vacancy creation
    • self-doping
    • application of hydrostatic pressure.




    Magnetic, Dielectric and Magnetoelectric Properties of Some Multiferroic Materials
    Structural, dielectric, magnetic, hyperfine and magnetoelectric (ME) properties of a few multiferroic based nanocomposites(NCs) and nanoparticles(NPs) have been investigated using state of the art experimental techniques.

    Multiferroic properties of BiFeO3 based NCs (with different ferrites) and NPs with substitution at different cationic sites have been studied. BiFeO3 is a multiferroic with ferroelectricity and antiferromagnetism at room temperature. Formation of NCs comprising BiFeO3 and ferrimagnetic SrFei12O19 induces quite large magnetic moment in antiferromagnetic BiFeO3 which enhances the overall magnetization and coercivity in NC system. Besides that, the magnetocapacitance(MC) which is a very important parameter for the presence of ME coupling in a material, is found to be increased with the increment of SrFe12O19 content in NCs. Similarly, NCs of BiFeO3 and CoFe2O4 also exhibit enhanced dielectric constant, magnetization, coercivity and MC in comparison with the pristine BiFeO3 and the enhancement is more with the increment of CoFe2O4 content. Besides nanocomposites, substitution of Tb3+ and Co3+ in Bi3+ and Fe3+ sites of BiFeO3 have been done to observe the effects in dielectric, magnetic and ME properties of BiFeOi3. Dielectric constant and magnetization of BiFeO3 are observed to be enhanced after doping. Also, MC is seen to be increased in the doped sample. In addition to BiFeO3, some doping effects on another multiferroic material TbMnO3, have been studied. TbMnO3 is a multiferroic with ferroelectric and antiferromagnetic transitions at very low temperatures(~ 27 and 42 K respectively). Co and Fe have been doped separately in Mn3+ site of TbMnO3 and dielectric, conductivity, magnetic, hyperfine and ME properties have been investigated. Both dielectric constant and conductivity have been increased after i doping with Co and Fe. Furthermore, substitution of Fe and Co result systematic shifting of Tb and Mn moment ordering temperatures and Co doping induces ferromagnetic interaction in antiferromagnetic i TbMnO3.

    In summary, this study reports the enhancement of overall multiferroic properties of BiFeO3 and TbMnO3. Better physical properties of substituted BiFeO3 and TbMnO3 NPs and BiFeO3 based NCs make them preferable for practical applications.

    Room temperature Mössbauer spectra of the pristine BiFeO3 and xSrFe12O19 - (1-x) BiFeO3 NCs(x = 0.1, 0.2, and 0.4). [Ref Anusree Das et al. Jou. Appl. Phys.,  119, 234102 (2016) ].



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