T., A. Ho and T., D. Thanh and Yu, Yikyung and D., M. Tartakovsky3 and T., O. Ho and Pham, Duc Thang and Le, Anh Tuan and Phan, The Long and S., C. Yu
(2015)
*Critical behavior and magnetocaloric effect of Pr1-xCaxMnO3.*
Journal Applied Physics, 117
(17D122).

## Abstract

The critical behavior of Pr1− x Ca x MnO3 samples with x = 0.25, 0.27, and 0.29 has been investigated. Detailed analyses of magnetic-field dependences of magnetization at temperatures around the paramagnetic-ferromagnetic transition, M(H, T), reveal that the samples undergo a second-order magnetic phase transition. The Arrott plot method predicts the values of critical parameters to be T C ≈ 118 K, β = 0.351 ± 0.003, γ = 1.372 ± 0.002, and δ = 4.90 ± 0.02 for x = 0.25; T C ≈ 116 K, β = 0.362 ± 0.002, γ = 1.132 ± 0.004, and δ = 4.09 ± 0.03 for x = 0.27; and T C ≈ 110 K, β = 0.521 ± 0.002, γ = 0.912 ± 0.005, and δ = 2.71 ± 0.02 for x = 0.29. The values of β = 0.351 (for x = 0.25) and β = 0.362 (for x = 0.27) are close to the value β = 0.365 expected for the 3D Heisenberg model, proving an existence of short-range ferromagnetic interactions in these samples. A slight increase in Ca-doping content (x = 0.29) leads to the shift of the β value (=0.521) towards that of the mean-field theory (with β = 0.5) characteristic of long-range ferromagnetic interactions. The samples also exhibit a magnetocaloric effect: around T C of Pr1− x Ca x MnO3 compounds, magnetic-entropy change reaches the maximum values of about 5.0, 4.1, and 2.5 J kg−1 K−1 for x = 0.25, 0.27, and 0.29, respectively, under an applied-field change of 50 kOe. Magnetic-field dependences of the maximum magnetic-entropy change (ΔS max) obey a power law |ΔS max(H)| ∝ Hn , where exponent values n = 0.68–0.74 are close to those obtained from the theoretical relation n = 1 + (β − 1)/(β + γ). T. A. Ho1, T. D. Thanh1,2, Yu3, D. M. , T. O. Ho4, P. D. Thang5, Anh-Tuan Le6, The-Long Phan1 and S. C. Yu

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 06:36 |

Last Modified: | 06 Jul 2016 06:36 |

URI: | http://eprints.uet.vnu.edu.vn/eprints/id/eprint/1798 |

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