Articles written in Bulletin of Materials Science

    • Structural, optical and magnetic properties of cobalt-doped CdSe nanoparticles

      Jaspal Singh N K Verma

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      Pure and Co-doped CdSe nanoparticles have been synthesized by hydrothermal technique. The synthesized nanoparticles have been characterized using X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV–Visible), photoluminescence spectroscopy (PL), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM) and superconducting quantum interference device (SQUID), at room temperature. From XRD analysis, pure and cobalt-doped CdSe nanoparticles have been found to be polycrystalline in nature and possess zinc blende phase having cubic structure. In addition to this, some peaks related to secondary phase or impurities such as cobalt diselenide (CoSe2) have also been observed. The calculated average crystallite size of the nanoparticles lies in the range, 3–21 nm, which is consistent with the results obtained from TEM analysis. The decrease in average crystallite size and blue shift in the band gap has been observed with Co-doping into the host CdSe nanoparticles. The magnetic analysis shows the ferromagnetic behaviour up to 10% of Co-doping concentration. The increase of Co content beyond 10% doping concentration leads to antiferromagnetic interactions between the Co ions, which suppress the ferromagnetism.

    • LiNbCoX (X = Al, Ga) quaternary Heusler compounds for high-temperature thermoelectric properties: a computational approach


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      Researchers have looked into quaternary Heusler (QH) compounds for their potential use in futuristic gadgets like photovoltaic cells, optical fibres, thermoelectric modules and spintronic sensors. As per such motivations and research interests, here we are presenting two recently reported Li-based QH compounds LiNbCoAl and LiNbCoGa which are stabilized into face-centred cubic structure of space group F-43m with semiconducting nature. These compounds exhibit high melting temperatures, showing the p-type semiconducting nature and are found to have advantageous thermoelectric capabilities in the high-temperature range. Additionally, the dynamical stability and appropriate elastic and mechanical characteristics for the foundation of effective thermoelectric modules in the temperature range of 1600 K enhance their scientific and technical scope. The electronic band structure is discussed along with the density of states for the betterunderstanding of the electrical properties. The thermodynamic response up to a temperature of 1600 K is also examined for understanding in terms of free energy, specific heat at constant volume and entropy. The special dependences in thetwo and three dimensions are applied and investigated to characterize the anisotropic nature. However all the required thermoelectric properties are calculated and presented, and the highest figure of merit value at 1600 K for both materials is 0.47 for LiNbCoAl and 0.56 for LiNbCoGa, respectively. As per their excellent practical properties, the current study asserts that both QH compounds should really be considered for energy conversion techniques in high-temperature environments. For the complete study prospectus, these materials are being disclosed for the first time here.

    • An observation of multiferroism in (1-x)BCZT–xNZFO-based 3-0 type composites


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      The development of multiferroic materials has opened up a plethora of possibilities for revolutionary futuristic magnetoelectric devices. The selection of an appropriate material for good multiferroic characteristics has always been a point of debate. Therefore, (1-x)Ba$_{0.85}$Ca$_{0.15}$Ti$_{0.9}$Zr$_{0.1}$O$_3$–xNi$_{0.5}$Zn$_{0.5}$Fe$_2$O$_4$ composites were thoroughly investigated in the this research work. The mixed phase of composites is revealed by powder X-ray diffraction, wherein NZFO and BCZT display the spinel phase and perovskite phase, respectively. Microstructural and elemental analyses show that the constituent phases of composites are distributed uniformly, with no evidence of impurity elements. The ferroelectric properties improved up to x = 0.3, after which lossy P–E loops were observed. The saturation magnetization rises from 7.358 to 38.916 emu g$^{-1}$ with an increase in ferrite concentration because the NZFO phase serves as the magnetization centre in composites. An increase in NZFO content resulted in improved ferroelectric and magnetic characteristics of the composites, whereas the value of dielectric constant decreases. The presence of a magnetodielectric (M–D) property indicates magnetoelectric (M–E) coupling at room temperature. With an addition of 20% NZFO, the highest value of M–D was found to be 8.75% and ${\gamma}$ = -2.3657 ${\times}$ 10$^{-4}$ g$^2$ emu$^{-2}$. The M–E coupling in the present composites resulted in an induced M–E voltage that can be tuned with external dc magnetic field. The maximum value of ${\alpha}_{max}$ = 1.46 mV cm$^{-1}$ Oe$^{-1}$ is obtained for x = 0.3 composite at magnetic field of 100 Oe. Further, it has been found that due to its soft magnetic nature and low conductivity, NZFO is a potential candidate as magnetostrictive phase of perovskite/magnetostrictive-based composites. Also, the M–E coupling in prepared composites has been established as a product property having a direct association with dynamic magnetostriction of the ferrite phase.

  • Bulletin of Materials Science | News

    • Dr Shanti Swarup Bhatnagar for Science and Technology

      Posted on October 12, 2020

      Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
      Chemical Sciences 2020

      Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
      Physical Sciences 2020

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

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