T., A. Ho and T., D. Thanh and T., V. Manh and T., O. Ho and Pham, Duc Thang and T., L. Phan and S., C. Yu (2015) Critical Behavior of La0.7Ca0.3MnO3 Nanoparticles. Materials Transactions, 56 (9). pp. 1331-1334.
Full text not available from this repository.Abstract
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.
| Item Type: | Article |
|---|---|
| Subjects: | Engineering Physics |
| Divisions: | Faculty of Engineering Physics and Nanotechnology (FEPN) |
| Depositing User: | Ms. Cam Le Tran Thi |
| Date Deposited: | 06 Jul 2016 06:35 |
| Last Modified: | 15 Jun 2017 01:55 |
| URI: | http://eprints.uet.vnu.edu.vn/eprints/id/eprint/1797 |
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