Colossal thermopower, spin states and delocalization effects in single layered La2−xSrxCoO4

Abdul Ahad; D. K. Shukla; F. Rahman; S. Majid; Tarachand; G. S. Okram; A. K. Sinha; D. M. Phase

doi:10.1016/j.actamat.2017.06.030

Colossal thermopower, spin states and delocalization effects in single layered La_2−xSr_xCoO₄

Abdul Ahad
, D. K. Shukla^*
, F. Rahman
, S. Majid
, Tarachand
, G. S. Okram
, A. K. Sinha
, D. M. Phase

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

26 Scopus citations

Abstract

Hole-doped La₂CoO₄ compounds have been widely studied due to their multifaceted behavior such as charge ordering, spin ordering and spin blockade. Hole doping in La₂CoO₄ causes appearance of the Co³⁺ along with the Co²⁺, which makes it an interesting model system for study of the spin-state transitions. In hole-doped samples, the spin-states of the Co³⁺ ions at large have been reported as the low or intermediate state. We report here a study on the Sr doping in La₂CoO₄. The Sr doping has been found to stabilize the crystal structure. By combining structural, electronic structure and electrical transport results, it is observed that the high-spin state is present in all the La_2−xSr_xCoO₄ (x = 0.5, 0.8, 0.9 and 1.0) samples. The high-spin state has been found to be concomitant with the delocalization of the e_g electrons. In addition, in these materials, a colossal thermopower has been observed for first time in the cryogenic temperatures.

Original language	English
Pages (from-to)	233-243
Number of pages	11
Journal	Acta Materialia
Volume	135
DOIs	https://doi.org/10.1016/j.actamat.2017.06.030
State	Published - 15 Aug 2017
Externally published	Yes

Bibliographical note

Publisher Copyright:
© 2017 Acta Materialia Inc.

Keywords

Conductivity phenomenon
Spin state transition
Thermopower
X-ray absorption spectra
X-ray diffraction

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Ceramics and Composites
Polymers and Plastics
Metals and Alloys

Access to Document

10.1016/j.actamat.2017.06.030

Cite this

@article{e0cf2f67ebce4148902a33ee10886e0b,

title = "Colossal thermopower, spin states and delocalization effects in single layered La2−xSrxCoO4",

abstract = "Hole-doped La2CoO4 compounds have been widely studied due to their multifaceted behavior such as charge ordering, spin ordering and spin blockade. Hole doping in La2CoO4 causes appearance of the Co3+ along with the Co2+, which makes it an interesting model system for study of the spin-state transitions. In hole-doped samples, the spin-states of the Co3+ ions at large have been reported as the low or intermediate state. We report here a study on the Sr doping in La2CoO4. The Sr doping has been found to stabilize the crystal structure. By combining structural, electronic structure and electrical transport results, it is observed that the high-spin state is present in all the La2−xSrxCoO4 (x = 0.5, 0.8, 0.9 and 1.0) samples. The high-spin state has been found to be concomitant with the delocalization of the eg electrons. In addition, in these materials, a colossal thermopower has been observed for first time in the cryogenic temperatures.",

keywords = "Conductivity phenomenon, Spin state transition, Thermopower, X-ray absorption spectra, X-ray diffraction",

author = "Abdul Ahad and Shukla, \{D. K.\} and F. Rahman and S. Majid and Tarachand and Okram, \{G. S.\} and Sinha, \{A. K.\} and Phase, \{D. M.\}",

note = "Publisher Copyright: {\textcopyright} 2017 Acta Materialia Inc.",

year = "2017",

month = aug,

day = "15",

doi = "10.1016/j.actamat.2017.06.030",

language = "English",

volume = "135",

pages = "233--243",

journal = "Acta Materialia",

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TY - JOUR

T1 - Colossal thermopower, spin states and delocalization effects in single layered La2−xSrxCoO4

AU - Ahad, Abdul

AU - Shukla, D. K.

AU - Rahman, F.

AU - Majid, S.

AU - Tarachand,

AU - Okram, G. S.

AU - Sinha, A. K.

AU - Phase, D. M.

PY - 2017/8/15

Y1 - 2017/8/15

N2 - Hole-doped La2CoO4 compounds have been widely studied due to their multifaceted behavior such as charge ordering, spin ordering and spin blockade. Hole doping in La2CoO4 causes appearance of the Co3+ along with the Co2+, which makes it an interesting model system for study of the spin-state transitions. In hole-doped samples, the spin-states of the Co3+ ions at large have been reported as the low or intermediate state. We report here a study on the Sr doping in La2CoO4. The Sr doping has been found to stabilize the crystal structure. By combining structural, electronic structure and electrical transport results, it is observed that the high-spin state is present in all the La2−xSrxCoO4 (x = 0.5, 0.8, 0.9 and 1.0) samples. The high-spin state has been found to be concomitant with the delocalization of the eg electrons. In addition, in these materials, a colossal thermopower has been observed for first time in the cryogenic temperatures.

AB - Hole-doped La2CoO4 compounds have been widely studied due to their multifaceted behavior such as charge ordering, spin ordering and spin blockade. Hole doping in La2CoO4 causes appearance of the Co3+ along with the Co2+, which makes it an interesting model system for study of the spin-state transitions. In hole-doped samples, the spin-states of the Co3+ ions at large have been reported as the low or intermediate state. We report here a study on the Sr doping in La2CoO4. The Sr doping has been found to stabilize the crystal structure. By combining structural, electronic structure and electrical transport results, it is observed that the high-spin state is present in all the La2−xSrxCoO4 (x = 0.5, 0.8, 0.9 and 1.0) samples. The high-spin state has been found to be concomitant with the delocalization of the eg electrons. In addition, in these materials, a colossal thermopower has been observed for first time in the cryogenic temperatures.

KW - Conductivity phenomenon

KW - Spin state transition

KW - Thermopower

KW - X-ray absorption spectra

KW - X-ray diffraction

UR - https://www.scopus.com/pages/publications/85021147842

U2 - 10.1016/j.actamat.2017.06.030

DO - 10.1016/j.actamat.2017.06.030

M3 - Article

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SN - 1359-6454

VL - 135

SP - 233

EP - 243

JO - Acta Materialia

JF - Acta Materialia

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