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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}

Journal Article · · AIP Advances
DOI:https://doi.org/10.1063/1.4896955· OSTI ID:22299638
; ; ;  [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)

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.

OSTI ID:
22299638
Journal Information:
AIP Advances, Vol. 4, Issue 9; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 2158-3226
Country of Publication:
United States
Language:
English