Magnetocaloric effect and magnetothermopower in the room temperature ferromagnet Pr0.6Sr0.4MnO3

D. V. Maheswar Repaka, T. S. Tripathi, M. Aparnadevi, R. Mahendiran*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

We have investigated magnetization (M), magnetocaloric effect (MCE), and magnetothermopower (MTEP) in polycrystalline Pr0.6Sr0.4MnO3, which shows a second-order paramagnetic to ferromagnetic transition near room temperature (T-C = 305 K). However, field-cooled M(T) within the long range ferromagnetic state shows an abrupt decrease at T-S = 86K for mu H-0 <3 T. The low temperature transition is first-order in nature as suggested by the hysteresis in M(T) and exothermic/endothermic peaks in differential thermal analysis for cooling and warming cycles. The anomaly at TS is attributed to a structural transition from orthorhombic to monoclinic phase. The magnetic entropy change (Delta S-m = S-m(mu H-0)-S-m(0)) shows a negative peak at T-C (normal MCE) and a positive spike (inverse MCE) at T-S. Delta S-m = -2.185 J/kg K (-3.416 J/kg K) with refrigeration capacity RC = 43.4 J/kg (103.324 J/kg) for field change of mu(0)Delta H = 1.5T (3T) at T-C = 304K is one of the largest values reported in manganites near room temperature. Thermopower (Q) is negative from 350K to 20K, which shows a rapid decrease at TC and a small cusp around TS in zero field. The MTEP [Delta Q/Q(0)] reaches a maximum value of 25% for mu(0)Delta H = 3T around T-C, which is much higher than 15% dc magnetoresistance for the same field change. A linear relation between MTEP and magnetoresistance and between Delta S-m and Delta Q are found near T-C. Further, ac magnetotransport in low dc magnetic fields (mu H-0

Original languageEnglish
Article number123915
Number of pages9
JournalJournal of Applied Physics
Volume112
Issue number12
DOIs
Publication statusPublished - 15 Dec 2012
MoE publication typeA1 Journal article-refereed

Keywords

  • COLOSSAL MAGNETORESISTANCE
  • THERMAL-CONDUCTIVITY
  • THERMOELECTRIC-POWER
  • TRANSPORT-PROPERTIES
  • THERMOPOWER
  • TRANSITION
  • MANGANITE
  • FILMS
  • MAGNETOIMPEDANCE
  • PEROVSKITES

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