TY - JOUR

T1 - Universal curves in assessing the order of magnetic transition of La0.7−xPrxCa0.3MnO3compounds exhibiting giant magnetocaloric effect

AU - Ho, T. A.

AU - Lim, S. H.

AU - Phan, T. L.

AU - Yu, S. C.

N1 - Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MEST) ( 2011-0028163 ).
Publisher Copyright:
© 2016 Elsevier B.V.

PY - 2017

Y1 - 2017

N2 - The magnetic properties of La0.7-xPrxCa0.3MnO3(x = 0.0, 0.2, 0.3, 0.4, and 0.5) compounds fabricated by a solid-state reaction are studied by using Arrott plots and universal curves. The Arrott plots near the Curie temperature show negative slopes over the entire magnetic field range up to 50 kOe, indicating a first-order magnetic phase transition (according to Banerjee's criterion) for the x = 0.0, 0.2, 0.3, and 0.4 samples. For the x = 0.5 sample, however, the plots show positive slopes at low magnetic fields below 10 kOe, indicating a second-order transition. These results are further checked by universal curves of the normalized entropy change versus reduced temperature. The universal curves show a divergence among the curves with different magnetic fields for a first-order magnetic transition, but for a second-order transition, they collapse onto the same curve. The Curie temperature, around which the maximum magnetic entropy change occurs, decreases continuously from 260 to 110 K as x increases from 0.0 to 0.5. In the same x range, the maximum entropy change measured at a magnetic field span of 50 kOe decreases from 10.70 to 7.14 J/kg K, but the relative cooling power increases from 278 to 380 J/kg under the same magnetic field span.

AB - The magnetic properties of La0.7-xPrxCa0.3MnO3(x = 0.0, 0.2, 0.3, 0.4, and 0.5) compounds fabricated by a solid-state reaction are studied by using Arrott plots and universal curves. The Arrott plots near the Curie temperature show negative slopes over the entire magnetic field range up to 50 kOe, indicating a first-order magnetic phase transition (according to Banerjee's criterion) for the x = 0.0, 0.2, 0.3, and 0.4 samples. For the x = 0.5 sample, however, the plots show positive slopes at low magnetic fields below 10 kOe, indicating a second-order transition. These results are further checked by universal curves of the normalized entropy change versus reduced temperature. The universal curves show a divergence among the curves with different magnetic fields for a first-order magnetic transition, but for a second-order transition, they collapse onto the same curve. The Curie temperature, around which the maximum magnetic entropy change occurs, decreases continuously from 260 to 110 K as x increases from 0.0 to 0.5. In the same x range, the maximum entropy change measured at a magnetic field span of 50 kOe decreases from 10.70 to 7.14 J/kg K, but the relative cooling power increases from 278 to 380 J/kg under the same magnetic field span.

KW - Magnetic phase transition

KW - Magnetic properties

KW - Magnetocaloric effect

KW - Perovskite manganites

UR - http://www.scopus.com/inward/record.url?scp=84995772997&partnerID=8YFLogxK

U2 - 10.1016/j.jallcom.2016.09.097

DO - 10.1016/j.jallcom.2016.09.097

M3 - Article

AN - SCOPUS:84995772997

VL - 692

SP - 687

EP - 692

JO - Journal of Alloys and Compounds

JF - Journal of Alloys and Compounds

SN - 0925-8388

ER -