Crystallographic features of the orbital-ordered, and charge-and-orbital- ordered states in Sr2-x Ndx Mn O4

Wataru Norimatsu, Yasumasa Koyama

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11 Citations (Scopus)

Abstract

The crystallographic features of the orbital-ordered and charge-and-orbital-ordered states in Sr2-x Ndx Mn O4 have been investigated by in situ observations, using a transmission electron microscope, in an attempt to understand the distinct characteristics of their electronic states. In the orbital-ordered state with orthorhombic symmetry, there exist four banded-domain-structure states, that is, two orthorhombic variant states (OI + OII) accompanying the C -type antiferromagnetic ordering at lower temperatures and (DT+ OI) coexistence and (OI + OII) states lacking magnetic ordering at higher temperatures, where DT represents the disordered tetragonal state and OI and OII the two orthorhombic variants. On the other hand, the stability of the charge-and-orbital-ordered state present for 0.25≤x≤0.43 is strongly suppressed when x>0.38. As a result of the strong suppression, the charge-exchange-type charge-and-orbital-ordered state is absent for x=0.5. The important features of the charge-and-orbital-ordered state are that it is basically characterized by incommensurate structural modulations and that round-shaped domains separated by disordered regions appear for 0.38<x≤0.43 near the DT state. On the basis of these data, the origin of the appearance of the four banded-structure states in the orbital-ordered state was attributed to a coupling between the local Jahn-Teller distortion and the long-range distortions, including a dilational one. In addition, we propose a model for the ground-state change between the orbital-ordered and charge-and-orbital-ordered states in terms of orbital degree of freedom.

Original languageEnglish
Article number235121
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume75
Issue number23
DOIs
Publication statusPublished - 2007 Jun 25
Externally publishedYes

Fingerprint

Jahn-Teller effect
orbitals
Electronic states
Ground state
Magnetization
Electron microscopes
Modulation
Temperature
charge exchange
degrees of freedom
electron microscopes
retarding
modulation
ground state
symmetry
electronics

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

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title = "Crystallographic features of the orbital-ordered, and charge-and-orbital- ordered states in Sr2-x Ndx Mn O4",
abstract = "The crystallographic features of the orbital-ordered and charge-and-orbital-ordered states in Sr2-x Ndx Mn O4 have been investigated by in situ observations, using a transmission electron microscope, in an attempt to understand the distinct characteristics of their electronic states. In the orbital-ordered state with orthorhombic symmetry, there exist four banded-domain-structure states, that is, two orthorhombic variant states (OI + OII) accompanying the C -type antiferromagnetic ordering at lower temperatures and (DT+ OI) coexistence and (OI + OII) states lacking magnetic ordering at higher temperatures, where DT represents the disordered tetragonal state and OI and OII the two orthorhombic variants. On the other hand, the stability of the charge-and-orbital-ordered state present for 0.25≤x≤0.43 is strongly suppressed when x>0.38. As a result of the strong suppression, the charge-exchange-type charge-and-orbital-ordered state is absent for x=0.5. The important features of the charge-and-orbital-ordered state are that it is basically characterized by incommensurate structural modulations and that round-shaped domains separated by disordered regions appear for 0.38",
author = "Wataru Norimatsu and Yasumasa Koyama",
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AU - Koyama, Yasumasa

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N2 - The crystallographic features of the orbital-ordered and charge-and-orbital-ordered states in Sr2-x Ndx Mn O4 have been investigated by in situ observations, using a transmission electron microscope, in an attempt to understand the distinct characteristics of their electronic states. In the orbital-ordered state with orthorhombic symmetry, there exist four banded-domain-structure states, that is, two orthorhombic variant states (OI + OII) accompanying the C -type antiferromagnetic ordering at lower temperatures and (DT+ OI) coexistence and (OI + OII) states lacking magnetic ordering at higher temperatures, where DT represents the disordered tetragonal state and OI and OII the two orthorhombic variants. On the other hand, the stability of the charge-and-orbital-ordered state present for 0.25≤x≤0.43 is strongly suppressed when x>0.38. As a result of the strong suppression, the charge-exchange-type charge-and-orbital-ordered state is absent for x=0.5. The important features of the charge-and-orbital-ordered state are that it is basically characterized by incommensurate structural modulations and that round-shaped domains separated by disordered regions appear for 0.38

AB - The crystallographic features of the orbital-ordered and charge-and-orbital-ordered states in Sr2-x Ndx Mn O4 have been investigated by in situ observations, using a transmission electron microscope, in an attempt to understand the distinct characteristics of their electronic states. In the orbital-ordered state with orthorhombic symmetry, there exist four banded-domain-structure states, that is, two orthorhombic variant states (OI + OII) accompanying the C -type antiferromagnetic ordering at lower temperatures and (DT+ OI) coexistence and (OI + OII) states lacking magnetic ordering at higher temperatures, where DT represents the disordered tetragonal state and OI and OII the two orthorhombic variants. On the other hand, the stability of the charge-and-orbital-ordered state present for 0.25≤x≤0.43 is strongly suppressed when x>0.38. As a result of the strong suppression, the charge-exchange-type charge-and-orbital-ordered state is absent for x=0.5. The important features of the charge-and-orbital-ordered state are that it is basically characterized by incommensurate structural modulations and that round-shaped domains separated by disordered regions appear for 0.38

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