Correlation between magnetoresistivity and magnetic entropy change in the 3D-Heisenberg ferromagnet CuCr2Te4

Abstract

We report a correlation between magnetoresistivity [Δρ mag = ρmag(H,T) - ρmag(0,T)] and magnetic entropy change [ΔSM = SM(H,T) - S M(0,T)] in the metallic spinel CuCr2Te4 which orders ferromagnetically below TC = 320 K. We find that Δρmag = KΔSM for several temperatures around TC with a temperature independent K, which suggests that magnetoresistivity arising from the suppression of spin disorder scattering scales with ΔSM. However, unlike expected theoretically, a clear correlation is not obtained between Δρmag and square of the reduced magnetization (M/Msat)2, where M sat is saturation magnetization at 0 K. A maximum magnetoresistance of -3.56% for μ0ΔH = 5 T and magnetic entropy change of -1.57 J/kg K occur at TC, which are typical values for itinerant ferromagnets. Critical exponent analysis using modified Arrott plots yield β = 0.371 ± 0.005 and γ = 1.312 ± 0.02 that are close to the 3D-Heisenberg (β = 0.365, γ = 1.336, and δ = 4.66) model. © 2013 AIP Publishing LLC.