Abstract
Electrical and thermal properties of Pr 2/3(Ba 1-xCs x) 1/3MnO 3 (0 ≤ x ≤ 0.25) manganite perovskites are reported here. Two insulator-metal (I-M) transitions (T P1 & T P2) are observed in the electrical resistivity (ρ) of the pristine Pr 2/3Ba 1/3MnO 3 (PBMO) sample, and they are systematically shifted to lower temperatures with increasing Cs substitution. An upturn in ρ is noticed below 50 K in these perovskites, presumably due to the combined effect of weak localization, electron-electron and electron-phonon scattering. It is found that the absolute value of room-temperature thermoelectric power (TEP) gradually decreases with increasing Cs content, implying the annihilation of the charge carriers with doping. An analysis of the electrical resistivity and thermoelectric power data indicates that the paramagnetic insulating state above T P1 is governed by the small polaron hopping due to a non-adiabatic process. It is argued that the electron-magnon scattering processes are responsible for low temperature metallic behavior of TEP. A distinct specific heat peak below T P1 is observed, attributed to the magnetic ordering, and its broadening with Cs-doping corresponds to the increase of magnetic inhomogeneity. Further, the temperature variation of thermal conductivity and the low temperature plateau in κ has been associated with the delocalization of Jahn-Teller polarons and transition from Umklapp scattering to a defect-limited scattering, respectively.
| Original language | English |
|---|---|
| Pages (from-to) | 179-186 |
| Number of pages | 8 |
| Journal | European Physical Journal B |
| Volume | 65 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 01-09-2008 |
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All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
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Electrical and thermal properties of Pr 2/3(Ba 1-xCs x) 1/3MnO 3 manganites. / Panwar, N.; Pandya, D. K.; Rao, A.; Wu, K. K.; Kaurav, N.; Kuo, Y. K.; Agarwal, S. K.
In: European Physical Journal B, Vol. 65, No. 2, 01.09.2008, p. 179-186.Research output: Contribution to journal › Article
TY - JOUR
T1 - Electrical and thermal properties of Pr 2/3(Ba 1-xCs x) 1/3MnO 3 manganites
AU - Panwar, N.
AU - Pandya, D. K.
AU - Rao, A.
AU - Wu, K. K.
AU - Kaurav, N.
AU - Kuo, Y. K.
AU - Agarwal, S. K.
PY - 2008/9/1
Y1 - 2008/9/1
N2 - Electrical and thermal properties of Pr 2/3(Ba 1-xCs x) 1/3MnO 3 (0 ≤ x ≤ 0.25) manganite perovskites are reported here. Two insulator-metal (I-M) transitions (T P1 & T P2) are observed in the electrical resistivity (ρ) of the pristine Pr 2/3Ba 1/3MnO 3 (PBMO) sample, and they are systematically shifted to lower temperatures with increasing Cs substitution. An upturn in ρ is noticed below 50 K in these perovskites, presumably due to the combined effect of weak localization, electron-electron and electron-phonon scattering. It is found that the absolute value of room-temperature thermoelectric power (TEP) gradually decreases with increasing Cs content, implying the annihilation of the charge carriers with doping. An analysis of the electrical resistivity and thermoelectric power data indicates that the paramagnetic insulating state above T P1 is governed by the small polaron hopping due to a non-adiabatic process. It is argued that the electron-magnon scattering processes are responsible for low temperature metallic behavior of TEP. A distinct specific heat peak below T P1 is observed, attributed to the magnetic ordering, and its broadening with Cs-doping corresponds to the increase of magnetic inhomogeneity. Further, the temperature variation of thermal conductivity and the low temperature plateau in κ has been associated with the delocalization of Jahn-Teller polarons and transition from Umklapp scattering to a defect-limited scattering, respectively.
AB - Electrical and thermal properties of Pr 2/3(Ba 1-xCs x) 1/3MnO 3 (0 ≤ x ≤ 0.25) manganite perovskites are reported here. Two insulator-metal (I-M) transitions (T P1 & T P2) are observed in the electrical resistivity (ρ) of the pristine Pr 2/3Ba 1/3MnO 3 (PBMO) sample, and they are systematically shifted to lower temperatures with increasing Cs substitution. An upturn in ρ is noticed below 50 K in these perovskites, presumably due to the combined effect of weak localization, electron-electron and electron-phonon scattering. It is found that the absolute value of room-temperature thermoelectric power (TEP) gradually decreases with increasing Cs content, implying the annihilation of the charge carriers with doping. An analysis of the electrical resistivity and thermoelectric power data indicates that the paramagnetic insulating state above T P1 is governed by the small polaron hopping due to a non-adiabatic process. It is argued that the electron-magnon scattering processes are responsible for low temperature metallic behavior of TEP. A distinct specific heat peak below T P1 is observed, attributed to the magnetic ordering, and its broadening with Cs-doping corresponds to the increase of magnetic inhomogeneity. Further, the temperature variation of thermal conductivity and the low temperature plateau in κ has been associated with the delocalization of Jahn-Teller polarons and transition from Umklapp scattering to a defect-limited scattering, respectively.
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U2 - 10.1140/epjb/e2008-00331-6
DO - 10.1140/epjb/e2008-00331-6
M3 - Article
VL - 65
SP - 179
EP - 186
JO - European Physical Journal B
JF - European Physical Journal B
SN - 1434-6028
IS - 2
ER -