• Udumula Subbarao

      Articles written in Journal of Chemical Sciences

    • Structure and properties of SmCu$_{6−x}$In$_{6+x}$ (𝑥 = 0, 1, 2)

      Udumula Subbarao Sebastian C Peter

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      High quality single crystals of SmCu6In6 were obtained from the reactions run in excess liquid indium and characterized by means of single crystal X-ray diffraction data. SmCu6In6 crystallizes in the YCu6In6 structure type, tetragonal space group $I4/mmm$ and lattice constants are 𝑎 = 𝑏 = 9.2036$(3) Å and 𝑐 = 5.4232(3) Å. SmCu$_{6−x}$In$_{6+x}$ (𝑥 = 0, 1, 2) compounds were obtained using arc melting and characterized using powder X-ray diffraction. Magnetic susceptibility data follow modified Curie-Weiss law behaviour above 50K and the experimentally measured magnetic moment values in SmCu4In8, SmCu5In7 and SmCu6In6 are 0.83 $\mu_B$, 1.45 $\mu_B$ and 0.90 $\mu_B$ per Sm atom, respectively. SmCu5In7 and SmCu6In6 compounds show antiferromagnetic ordering at $T_N = 7.8$ K, and no magnetic ordering was observed for SmCu4In8 down to 2 K. Electrical resistivity measurements show that all compounds are of metallic nature.

    • Crystal growth, structure and magnetic properties of Sm3Ni5Al19: A compound in the Sm$_{2n+m}$Ni$_{4n+m}$Al$_{15n+4m}$ homologous series

      Udumula Subbarao Aloke Kumar Ghosh Sumanta Sarkar Sebastian C Peter

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      Sm3Ni5Al19 was obtained as large rod shaped single crystals from reactive aluminium flux. Single crystal X-ray diffraction suggests that Sm3Ni5Al19 crystallizes in the Gd3Ni5Al19 structure type, orthorhombic space group $Cmcm$ and lattice constants 𝑎 = 4.0974(1) Å, 𝑏 = 16.0172(6)Å and 𝑐 = 27.0774(10) Å. Sm3Ni5Al19 is a member of the Sm$_{2n+m}$Ni$_{4n+m}$Al$_{15n+4m}$ series with n = 1 and m = 1. The crystal structure of Sm3Ni5Al19 consists of SmNiAl4 and Sm2Al4Al15 slabs intergrown along the 𝑏-axis. Magnetic susceptibility data on Sm3Ni5Al19 confirms the paramagnetic nature with a complicated magnetic ordering below 18 K. The inverse susceptibility data follows modified Curie-Weiss law above 150 K with effective magnetic moment 1.3 $\mu_{\text{B}}$/Sm atoms suggests trivalent Sm atoms.

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