A thermogravimetric study of the influence of internal stresses on oxygen variations in Ln{sub 2-x}Ce{sub x}CuO{sub 4}

Journal Article · Wed Feb 01 04:00:00 EST 1995 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1006/jssc.1995.1074· OSTI ID:518223

Zhu, Y T; Manthiram, A ^[1]

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1. Univ. of Texas, Austin, TX (United States)

The variation with temperature of oxygen content in the electron-doped superconductors Ln{sub 2-x}Ce{sub x}CuO{sub 4} (Ln = lanthanide) have been investigated systematically by thermogravimetric analysis. The tendency to lose oxygen generally decreases with increasing Ce content or decreasing Ln{sup 3+} size due to a decreasing degree of internal stresses resulting from an improved bond length matching between the (Ln, Ce)-O and Cu-O bonds; this is supported by bond valence sum calculations. With smaller a lattice parameters as in Gd{sub 2-x}Ce{sub x}CuO{sub 4}, however, an increasing electrostatic repulsion between the interstitial octahedral-site and the normal tetrahedral-site oxygen atoms forces the excess interstitial oxygen atoms to be lost at lower temperatures. It also causes the oxygen loss to occur in two steps, one corresponding to the interstitial oxygen and the other to the tetrahedral-site oxygen atoms. In contrast, the oxygen loss occurs smoothly in one step for larger a lattice parameters as in LaNd{sub 1-x}Ce{sub x}CuO{sub 4}.

• OSTI ID: 518223
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 2 Vol. 114; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERIUM OXIDES
COPPER OXIDES
CRYSTAL STRUCTURE
GADOLINIUM OXIDES
LANTHANUM OXIDES
LATTICE PARAMETERS
NEODYMIUM OXIDES
STRESSES
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
VALENCE