Critical behavior near room temperature in La 0.75 Ca 0.05 Na 0.20 MnO 3 sample.

The critical behavior of La 0.75 Ca 0.05 Na 0.20 MnO 3 was studied at around room temperature via magnetization measurements. From the relative slope, we deduced that the Tricritical Mean-Field model was the most suitable model. The estimated critical exponents were found to be β = 0.24 ± 0.004, γ = 0.98 ± 0.065 and δ = 5.08 at T C = 300 K. These critical exponents satisfied the Widom scaling relation δ = 1 + γ / β , implying the reliability of our values. Based on the critical exponents, the magnetization-field-temperature ( M - μ 0 H - T ) data around T C collapsed into two curves, obeying the single scaling equation with ε = ( T - T C )/ T C being the reduced temperature. These results suggest short-range interaction in our sample.