1
|
Singh H, Skoulatos M, Joshi DC, Pramanik P, Roy-Chowdhury M, Ghosh S, Jena SK, Dey JK, Thota S. Magnetic exchange interactions and non-Debye relaxation in spin-3/2 frustrated Kagomé magnet Co 3V 2O 8. J Phys Condens Matter 2024; 36:315601. [PMID: 38653255 DOI: 10.1088/1361-648x/ad4223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 04/23/2024] [Indexed: 04/25/2024]
Abstract
We report the experimental determination of the magnetic exchange parameter (J/kB= 2.88 ± 0.02 K) for the Spin-3/2 ferromagnetic (FM) Kagomé lattice system: Co3V2O8using the temperature dependence of dc-magnetic susceptibilityχ(T) data by employing the fundamental Heisenberg linear chain model. Our results are quite consistent with the theoretically reported nearest neighbor dominant FM exchange coupling strengthJex-NN∼2.45 K. Five different magnetic phase transitions (6.2-11.2 K) and spin-flip transitions (9.6-7.7 kOe) have been probed using the∂(χT)/∂Tvs.T, heat capacity (CP-T) and differential isothermal magnetization curves. Among such sequence of transitions, the prominent ones being incommensurate antiferromagnetic (AFM) state at 11.2 K, commensurate AFM state at 8.8 K, and commensurate FM state across 6.2 K. All the successive magnetic phase transitions have been mapped onto a single H-T plane through which one can easily distinguish the above-mentioned different phases. The magnetic contribution of theCP-TnearTN(11.2 K) has been analyzed using the power-law expressionCM=A|T-TN|-αresulting in the critical exponentα= 0.18 ± 0.01 (0.15 ± 0.003) forTTN), respectively for the Co3V2O8. It is interesting to note that non-Debye type dipole relaxation is quite prominent in Co3V2O8and was evident from the Kohlrausch-Williams-Watts analysis of complex modulus and impedance spectra (0⩽β⩽1). Mott's variable-range hopping of charge carriers process is evident through the resistivity analysis (ρac-T-1/4) in the temperature range 275 ∘C-350 ∘C. Moreover, the frequency-dependent analysis ofσac(ω) follows Jonscher's power law yielding two distinct activation energies (Ea∼0.37 and 2.29 eV) between the temperature range 39 ∘C-99 ∘C and 240 ∘C-321 ∘C.
Collapse
Affiliation(s)
- H Singh
- Department of Physics, Indian Institute of Technology, Guwahati 781039, Assam, India
| | - M Skoulatos
- Heinz Maier-Leibnitz Zentrum (MLZ) and Physics Department, Technical University of Munich, D-85748 Garching, Germany
| | - D C Joshi
- Department of Physics, Indian Institute of Technology, Guwahati 781039, Assam, India
| | - P Pramanik
- Department of Physics, Indian Institute of Technology, Guwahati 781039, Assam, India
| | - M Roy-Chowdhury
- Department of Physics, Indian Institute of Technology, Guwahati 781039, Assam, India
| | - S Ghosh
- Department of Physics, Indian Institute of Technology, Guwahati 781039, Assam, India
| | - S K Jena
- Department of Physics, Indian Institute of Technology, Guwahati 781039, Assam, India
| | - J K Dey
- Department of Physics, Indian Institute of Technology, Guwahati 781039, Assam, India
| | - S Thota
- Department of Physics, Indian Institute of Technology, Guwahati 781039, Assam, India
| |
Collapse
|
2
|
Plášil J, Petříček V, Majzlan J. A commensurately modulated structure of parabutlerite, Fe IIISO 4(OH)·2H 2O. Acta Crystallogr B Struct Sci Cryst Eng Mater 2017; 73:856-862. [PMID: 28980989 DOI: 10.1107/s2052520617007156] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 05/15/2017] [Indexed: 06/07/2023]
Abstract
Parabutlerite, orthorhombic FeIIISO4(OH)·2H2O, has been reinvestigated using single-crystal X-ray diffraction. The structure of parabutlerite is commensurately modulated, with a = 20.0789 (8), b = 7.4024 (7), c = 7.2294 (15) Å and q = 0.4b*. The superstructure has been determined, using a superspace approach, as having the superspace group Pnma(0β0)s0s and t0 = 1/20, and refined to R = 0.0295 for 2392 main reflections with I > 3σ(I). The structure consists of infinite chains of Fe octahedra that are linked via vertices (OH groups); these chains are encased from both sides by SO4 tetrahedra. The displacive modulation of atoms in parabutlerite is connected with a tilt of the chains around the b axis towards the adjacent chains due to the accommodation of an energetically more favorable hydrogen-bond geometry.
Collapse
Affiliation(s)
- Jakub Plášil
- Institute of Physics ASCR, v.v.i., Na Slovance 2, Praha 8, 18221, Czech Republic
| | - Václav Petříček
- Institute of Physics ASCR, v.v.i., Na Slovance 2, Praha 8, 18221, Czech Republic
| | - Juraj Majzlan
- Institut für Geowissenschaften, Friedrich-Schiller-Universität Jena, Burgweg 11, Jena, 07749, Germany
| |
Collapse
|
3
|
Kim NY, Jeong HY, Kim JH, Kim G, Shin HS, Lee Z. Evidence of Local Commensurate State with Lattice Match of Graphene on Hexagonal Boron Nitride. ACS Nano 2017; 11:7084-7090. [PMID: 28613831 DOI: 10.1021/acsnano.7b02716] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Transition to a commensurate state changes the local symmetry periodicity on two-dimensional van der Waals superstructures, evoking distinctive properties far beyond individual layers. We investigate the morphology of moiré superstructures of graphene on hexagonal boron nitride (hBN) with a low twist angle (≈0°) through moiré fringe analyses with dark field transmission electron microscopy. The moiré fringes exhibit local variation, suggesting that the interaction between graphene and hBN depends on the stacking configuration and that local transition to the commensurate state occurs through the reduced crystalline mismatch (that is, by lattice stretching and twisting on the graphene lattices). This moiré superstructure analysis suggests an inventive method for studying the interaction between stacked van der Waals layers and for discerning the altered electronic and optical properties of graphene on hBN superstructures with a low twist angle, even at low magnification.
Collapse
Affiliation(s)
- Na Yeon Kim
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS) , Ulsan 44919, Republic of Korea
| | | | | | | | - Hyeon Suk Shin
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS) , Ulsan 44919, Republic of Korea
| | - Zonghoon Lee
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS) , Ulsan 44919, Republic of Korea
| |
Collapse
|