Magnetic entropy change and critical exponents in double perovskite Y2NiMnO6

We report the magnetic entropy change (ΔSM) and the critical exponents in the double perovskite manganite Y2NiMnO6 with a ferromagnetic to paramagnetic transition TC~85K. For a magnetic field change ΔH=80kOe, a maximum magnetic entropy change ΔSM=−6.57J/kgK is recorded around TC. The critical exponents β=0.363±0.05 and γ=1.331±0.09 obtained from power law fitting to spontaneous magnetization MS(T) and the inverse initial susceptibility χ0−1(T) satisfy well to values derived for a 3D-Heisenberg ferromagnet. The critical exponent δ=4.761±0.129 is determined from the isothermal magnetization at TC. The scaling exponents corresponding to second order phase transition are consistent with the exponents from Kouvel-Fisher analysis and satisfy Widom׳s scaling relation δ=1+(γ/β). Additionally, they also satisfy the single scaling equation M(H,ϵ)=ϵβf±(H/ϵβ+γ) according to which the magnetization-field-temperature data around TC should collapse into two curves for temperatures below and above TC.