X-ray absorption near edge spectra (XANES) and magnetization of Zn doped
MnV2O4 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 \b{eta}, {\gamma} and
{\delta} 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 Mn0.95Zn0.05V2O4 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.Comment: 19 pages, 9 Figures. arXiv admin note: substantial text overlap with
arXiv:1311.402
