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Title: Effect of Zn doping on the magneto-caloric effect and critical constants of Mott insulator MnV{sub 2}O{sub 4}

X-ray absorption near edge spectra (XANES) and magnetization of Zn doped MnV{sub 2}O{sub 4} have been measured and from the magnetic measurement the critical exponents and magnetocaloric effect have been estimated. The XANES study indicates that Zn doping does not change the valence states in Mn and V. It has been shown that the obtained values of critical exponents β, γ and δ do not belong to universal class and the values are in between the 3D Heisenberg model and the mean field interaction model. The magnetization data follow the scaling equation and collapse into two branches indicating that the calculated critical exponents and critical temperature are unambiguous and intrinsic to the system. All the samples show large magneto-caloric effect. The second peak in magneto-caloric curve of Mn{sub 0.95}Zn{sub 0.05}V{sub 2}O{sub 4} is due to the strong coupling between orbital and spin degrees of freedom. But 10% Zn doping reduces the residual spins on the V-V pairs resulting the decrease of coupling between orbital and spin degrees of freedom.
Authors:
; ; ;  [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. Department of Applied Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi-221005 (India)
  2. Indus Synchrotron Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore - 452013 (India)
  3. Department of Physics, Banaras Hindu University, Varanasi-221005 (India)
  4. Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai – 400 094 (India)
  5. Department of CMP and MS, Tata Institute of Fundamental Research, Mumbai-400005 (India)
Publication Date:
OSTI Identifier:
22299638
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 4; Journal Issue: 9; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION; ABSORPTION SPECTROSCOPY; CRITICAL TEMPERATURE; DEGREES OF FREEDOM; DOPED MATERIALS; HEISENBERG MODEL; INTERACTIONS; MAGNETIC PROPERTIES; MAGNETIZATION; SPECTRA; SPIN; X RADIATION; X-RAY SPECTROSCOPY