| 학회 |
한국재료학회 |
| 학술대회 |
2020년 가을 (11/18 ~ 11/20, 휘닉스 제주 섭지코지) |
| 권호 |
26권 1호 |
| 발표분야 |
D. 구조 재료 분과 |
| 제목 |
Investigation the effect of structural inhomogeneities on the magnetic and magnetocaloric properties of La1.4Nd1.4-xCa1.6Mn2O7 (0.0 ≤ x ≤ 0.4) bilayer manganites |
| 초록 |
Here we report the structural, magnetic and magnetocaloric properties of the polycrystalline La1.4Nd1.4-xCa1.6Mn2O7 (0.0 ≤ x ≤ 0.4) samples. The samples were prepared through the conventional ceramic heating method. The X-ray diffraction profiles of all the compositions revealed the Ruddlesden-Popper bilayer phase with tetragonal crystal symmetry. The Scanning electron microscopy of the samples suggested a thoroughly connected matrix with ambiguous grain boundaries. The temperature dependent magnetization unfolded phase segregated states near transition temperature. The contribution of these heterogeneities evaluated by employing the Griffith’s model, the singularity constant (λ) consistently increased with increasing the dopant concentration. Arrott plots of the pure compound suggested second order transition however the transition shifted towards the first order nature upon doping the Neodymium (Nd). The change in the magnetic entropy for the parent compound was found to be 3.2 J kg-1K-1 which significantly enhanced upto 5.8 J kg-1K-1 for x = 0.4 composition under an applied field of 2.5 T. For the doped samples the relative cooling power of the samples also elevated several folds compared to the parent compound. The proposed approach for the estimation of Griffith’s singularity in the bilayer structure of the manganites has never been discussed previously and the enhancement of magnetocaloric effects upon Nd doping in these compounds is important for the technological applications. |
| 저자 |
Akshay Kumar, 신민지, 구본흔
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| 소속 |
Changwon National Univ. |
| 키워드 |
Griffith’s model; Ruddlesden-Popper Phase; Arrott plots; transition temperature; magnetic entropy
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| E-Mail |
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