The nature of charge ordering in rare earth manganates and its strong dependence on the size of the A-site cations

Journal Article · Sat Mar 01 04:00:00 EST 1997 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1006/jssc.1997.7351· OSTI ID:569212

Kumar, N ^[1]; Rao, C N.R. ^[2]

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1. Raman Research Inst., Bangalore (India)
2. Indian Inst. of Science, Bangalore (India)

Charge ordering in rare earth manganates of the type Ln{sub 0.5}A{sub 0.5}MnO{sub 3} (Ln = rare earth, A=alkaline earth) is highly sensitive to the average radius of the A-site cations, . In the small regime (e.g., Y{sub 0.5}Ca{sub 0.5}MnO{sub 3}), charge ordering occurs in the paramagnetic state, the transformation to an antiferro-magnetic state occurring at still lower temperatures. At moderate values (e.g., Nd{sub 0.5}Sr{sub 0.5}MnO{sub 3}), a ferromagnetic metallic state transforms to a charge-ordered antiferromagnetic state with cooling. These two distinct types of charge ordering and associated properties are explained in terms of the variation of the exchange couplings J{sub FM} and J{sub AFM} with and the invariance of the single-ion Jahn-Teller energy with . A qualitative temperature- phase diagram, consistent with the experimental observations, has been constructed to describe the properties of the manganates in the different <{sup A}> regimes.

• OSTI ID: 569212
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 2 Vol. 129; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CALCIUM COMPOUNDS
COOLING
MANGANATES
PARAMAGNETISM
PHASE DIAGRAMS
YTTRIUM COMPOUNDS