부산대학교 도서관

We report the doping effect of divalent cation Cd2+ at Nd-site of intermediate bandwidth manganite system NdMnO3 through the temperature- and magnetic field-dependent magnetization measurements. The parent compound shows paramagnetic-antiferromagnetic transition at 56 K, whereas Cd doped samples show the paramagnetic-ferromagnetic transition with fluctuating TC. During this transition, Nd1-xCdxMnO3 (x=0.1 and 0.2) samples exhibit first order nature, whereas Nd1-xCdxMnO3 (x=0.3 and 0.4) samples exhibit second order nature. It confirms a crossover from first order transition to second order transition while x=0.2 to x=0.3. By having first order transition, x=0.2 sample exhibits high magnetic entropy change of 3.62 J kg-1 K-1 for the magnetic field change of 5 T out of all compositions. By having second order transitions, x=0.4 sample exhibits a high relative cooling power of 319.71 J kg-1 for the magnetic field change of 5 T out of all the compositions. The critical behavior of second order transition of x=0.3 and 0.4 samples has been analyzed using Arrott and Kouvel-Fisher plots. The estimated critical exponents of these samples are nearly matched with the mean free model, which can be explained by the existence of dipole-dipole interaction by the Cd doping which strengthens long range ferromagnetic interactions between the spins. [ABSTRACT FROM AUTHOR]