TY  - JOUR
ID  - SisLab1797
UR  - doi:10.2320/matertrans.MA201552
IS  - 9
A1  - T., A. Ho
A1  - T., D. Thanh
A1  - T., V. Manh
A1  - T., O. Ho
A1  - Pham, Duc Thang
A1  - T., L. Phan
A1  - S., C. Yu
Y1  - 2015///
N2  - We used the modified Arrott plot method to analyze magnetic-field dependences of magnetization, M(H), around the ferromagneticparamagnetic
(FM-PM) phase-transition temperature (TC) of three nanocrystalline La0.7Ca0.3MnO3 samples with average crystallite sizes d = 40,
23, and 16 nm. The analyses obtained the values of critical parameters to be TC µ 261 K, ¢ = 0.485 « 0.005, £ = 1.051 « 0.094 and ¤ = 3.1 «
0.1 for the sample with d = 40 nm, TC µ 252 K, ¢ = 0.525 « 0.010, £ = 0.893 « 0.139 and ¤ = 2.7 « 0.1 for d = 23 nm, and TC µ 236 K,
¢ = 0.621 « 0.008, £ = 0.825 « 0.007 and ¤ = 2.2 « 0.2 for d = 16 nm. With these critical values, the M(H) data points around TC of the
samples fall into two universal branches of a scaling function M(H, ¾) = «¾«
¢f«(H/«¾«
¢+£
), with ¾ = (T ¹ TC)/TC, f+ for T > TC and f¹ for T < TC.
The results reveal that the crystallite-size reduction of nanoparticles decreases the TC value. This is ascribed to the decrease of FM doubleexchange
interactions between Mn3+ and Mn4+ ions, which is related to the ¢ change from 0.485 for d = 40 nm to 0.621 for d = 16 nm,
corresponding to the change in FM order from the long-range type to the short-range one.
JF  - Materials Transactions
VL  - 56
TI  - Critical Behavior of La0.7Ca0.3MnO3 Nanoparticles
SP  - 1331
AV  - none
EP  - 1334
ER  -