TY - GEN
T1 - Crystallographic features of the charge-orbital-ordered state in the highly-correlated electronic system Ca1-xPrxMnO3
AU - Kojima, Kentaro
AU - Inoue, Yasuhide
AU - Arao, Masazumi
AU - Koyama, Yasumasa
N1 - Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 2014
Y1 - 2014
N2 - The charge-exchange-type orbital-ordered (CEOO) state accompanying antiferromagnetic ordering has been reported in the highly-correlated electronic system Ca1-xPrxMnO3 (CPMO) with the simple perovskite structure. The feature of the CEOO state in CPMO is that the state is present in the wide Pr-content range of 0.30 ≤ x ≤ 0.70. Although the Zener-polaron model was proposed for the CEOO state at x = 0.60, the detailed features of the CEOO state, particularly for lower Pr contents, have not been understood sufficiently. We have thus investigated the crystallographic features of the CEOO state in CPMO with 0.40 ≤ x ≤ 0.50, mainly by transmission electron microscopy. It was found that, when the temperature was lowered from the disordered state, incommensurate satellite reflections characterizing the CEOO state appeared in electron diffraction patterns below about 250 K in CPMO. The careful analysis of the reflections indicated that the CEOO state for 0.40 ≤ x ≤ 0.45 was different from that for 0.45 ≤ x ≤ 0.50. Concretely, the former CEOO state accompanied only a transverse lattice modulation, while both transverse and longitudinal modulations with different wave vectors appeared in the latter state. This implies that the state for 0.40 ≤ x ≤ 0.45 can be regarded as an orbital-modulated (OM) state without a charge modulation. It is thus understood that an increase in the Pr content leads to the OM-to-CEOO state change below about 250 K around x = 0.45.
AB - The charge-exchange-type orbital-ordered (CEOO) state accompanying antiferromagnetic ordering has been reported in the highly-correlated electronic system Ca1-xPrxMnO3 (CPMO) with the simple perovskite structure. The feature of the CEOO state in CPMO is that the state is present in the wide Pr-content range of 0.30 ≤ x ≤ 0.70. Although the Zener-polaron model was proposed for the CEOO state at x = 0.60, the detailed features of the CEOO state, particularly for lower Pr contents, have not been understood sufficiently. We have thus investigated the crystallographic features of the CEOO state in CPMO with 0.40 ≤ x ≤ 0.50, mainly by transmission electron microscopy. It was found that, when the temperature was lowered from the disordered state, incommensurate satellite reflections characterizing the CEOO state appeared in electron diffraction patterns below about 250 K in CPMO. The careful analysis of the reflections indicated that the CEOO state for 0.40 ≤ x ≤ 0.45 was different from that for 0.45 ≤ x ≤ 0.50. Concretely, the former CEOO state accompanied only a transverse lattice modulation, while both transverse and longitudinal modulations with different wave vectors appeared in the latter state. This implies that the state for 0.40 ≤ x ≤ 0.45 can be regarded as an orbital-modulated (OM) state without a charge modulation. It is thus understood that an increase in the Pr content leads to the OM-to-CEOO state change below about 250 K around x = 0.45.
KW - Charge-exchange-type orbital-ordered state
KW - Highly-correlated electronic system
KW - Orbital modulated state
KW - Simple perovskite manganite
KW - Transmission electron microscopy
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U2 - 10.4028/www.scientific.net/AMR.922.376
DO - 10.4028/www.scientific.net/AMR.922.376
M3 - Conference contribution
AN - SCOPUS:84901494718
SN - 9783038350743
T3 - Advanced Materials Research
SP - 376
EP - 382
BT - THERMEC 2013 Supplement
PB - Trans Tech Publications
T2 - 8th International Conference on Processing and Manufacturing of Advanced Materials: Processing, Fabrication, Properties, Applications, THERMEC 2013
Y2 - 2 December 2013 through 6 December 2013
ER -