Critical exponents and the correlation length in the manganite spin glass Eu_(0.5)Ba_(0.5)MnO_3

摘要

The critical regime of the half doped manganite spin glass Eu_(0.5)Ba_(0.5)MnO_3 is investigated using a combination of the linear and nonlinear magnetic susceptibilities. The divergence of the third-ordered susceptibility (χ_3) signifying the onset of a conventional freezing transition is experimentally demonstrated. The divergence in χ_3, dynamical scaling of the linear susceptibility, and relevant scaling equations are used to determine the critical exponents associated with this freezing transition, the values of which match well with the three-dimensional Ising universality class. Magnetic-field dependence of the spin glass response function is used to estimate the spin-correlation length, which is seen to be larger than the charge and/or orbital correlation length reported in this system.