Browsing by Author "K. Moovendaran"

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Anisotropic Magnetic Properties of Nonsymmorphic Semimetallic Single Crystal NdSbTe
(American Chemical Society, 2020) Raman Sankar; I. Panneer Muthuselvam; Karthik Rajagopal; K. Ramesh Babu; G. Senthil Murugan; Khasim Saheb Bayikadi; K. Moovendaran; Chien Ting Wu; Guang-Yu Guo
The crystal structure and magnetic, electronic, and thermal properties of a NdSbTe single crystal were examined by X-ray diffraction, magnetic and specific heat Cp(T) measurements, and density functional theory (DFT) calculations. NdSbTe undergoes an antiferromagnetic ordering at TN ≈ 2.9 K, which is obviously shown from χ(T) and Cp(T). With increasing H, a spin-flop transition is induced along the c axis, and subsequently AFM disappeared at H ≤ 0.4 T and H ≤ 2.5 T along H≈c and H≈ab, respectively. This remarkable observation shows that the ordered Nd3+ moments lie in the c axis and that there is the existence of an anisotropy scenario. The estimated magnetic anisotropy with χ≈c (0.63)/χ≈ab (0.036) is 17.5 at temperature 1.8 K. An analysis of specific heat capacity reveals the significant contribution of crystal field effects at high temperature. We carried out DFT calculations to predict the magnetic ground state and the electronic properties of NdSbTe. Our calculations revealed that the magnetic ground state is AFM with spins aligned ferromagnetically along the b axis and antiferromagnetically along the c axis. The calculated electronic band of NdSbTe exhibits a Dirac semimetal material nature. © 2020 American Chemical Society.
Crystal growth and magnetic properties of the coupled alternating S =1 spin chain Sr2Ni(Se O3)3
(American Physical Society, 2023) R. Madhumathy; K. Saranya; K. Moovendaran; K. Ramesh Babu; Arpita Rana; Kwang-Yong Choi; Heung-Sik Kim; Wei-Tin Chen; M. Ponmurugan; R. Sankar; I. Panneer Muthuselvam
The structural, magnetic, and thermodynamic properties of a quasi-one-dimensional (1D) S=1 alternating spin chain compound Sr2Ni(SeO3)3 are investigated by using synchrotron x-ray powder diffraction, magnetic susceptibility χ(H,T), and heat capacity CP(H,T) measurements together with density functional theory (DFT) calculations. The χ(H,T) and CP(H,T) data reveal long-range antiferromagnetic order at TN=3.4(3) K and short-range order at Tm≈7.8K. The short-range magnetic order together with 95% of spin entropy release above TN signifies the importance of 1D spin correlations persisting to ∼8TN. Theoretical DFT calculations with generalized gradient approximation determine leading exchange interactions, suggesting that interchain interactions are responsible for the observed long-range magnetic ordering. In addition, the temperature-field phase diagram of Sr2Ni(SeO3)3 is determined based on the χ(T,H) and CP(T,H) data. Interestingly, a nonmonotonic phase boundary of Tm is found for an external field applied along a hard axis. Our results suggest that the ground state and magnetic behavior of Sr2Ni(SeO3)3 rely on the interplay of single-ion anisotropy, bond alternation, and interchain interactions. © 2023 American Physical Society.
Spin-singlet ground state of the coupled Jeff = 12 alternating chain system Sr2 Co(SeO3)3
(American Physical Society, 2022) I. Panneer Muthuselvam; R. Madhumathy; K. Saranya; K. Moovendaran; Suheon Lee; Kwang-Yong Choi; Wei-Tin Chen; Chin-Wei Wang; Peng-Jen Chen; M. Ponmurugan; Min-Nan Ou; Yang-Yuan Chen; Heung-Sik Kim; R. Sankar
We report a detailed study of the structural, magnetic, thermodynamic, and electronic properties of a coupled Jeff = 12 alternating chain Sr2Co(SeO3)3 compound using magnetic susceptibility χ(T), magnetic specific heat Cm(T), magnetization, and neutron diffraction measurements along with first-principles calculations. The first-principles calculations based on the density functional theory suggest that Sr2Co(SeO3)3 forms a quasi-one-dimensional chain with bond alternation and interchain interactions. χ(T), Cm(T), and neutron powder diffraction measurements confirm that no long-range magnetic ordering occurs down to 100 mK. Instead, a maximum in χ(T) and Cm(T) and an exponential drop of χ(T) and Cp(T) as T→0 K point to a spin-singlet ground state. The analysis of χ(T) and Cm(T) based on a J1-J2 alternating Heisenberg model shows the bond alternation α=J2/J1≈0.7 and a spin gap of Δ≈3 K. Our work demonstrates that Sr2Co(SeO3)3 is a coupled alternating chain system based on spin-orbit entangled Jeff = 12. © 2022 American Physical Society.
Structural, magnetic, and electronic properties of a GdAsSe single crystal: Experimental and theoretical studies
(American Physical Society, 2024) R. Kalaivanan; Balaji Venkatesan; B. Dundi Sri Chandana; Rajesh Kumar Ulaganathan; G. Senthil Murugan; K. Moovendaran; Joydev Khatua; Li-Hsin Su; W. Zhou; Xiaofeng Xu; Chia-Seng Chang; Tien-Ming Chuang; Yoshiyuki Iizuka; I. Panneer Muthuselvam; Horng-Tay Jeng; Kwang-Yong Choi; Raman Sankar
We report high-quality single-crystal growth, x-ray diffraction, magnetic susceptibility [χ(T,H)], magnetization [M(H)], heat capacity [CP(T,H)], electrical resistivity [ρ(T,H)], and electron spin resonance (ESR) measurements of GdAsSe as functions of temperature and magnetic field. We identify an antiferromagnetic phase transition at TN∼11.9±0.2 K and construct magnetic phase diagrams for H