Defects and metastable structures of MgAl{sub 2}O{sub 4}

Conference · Sat Jul 01 04:00:00 EDT 1995

OSTI ID:93980

Chen, S P; Yan, M ^[1]; Grimes, R W; Vyas, S ^[2]; Gale, J D ^[3]

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1. Los Alamos National Lab., NM (United States)
2. The Royal Institution of Great Britain, London (United Kingdom)
3. Imperial Coll., London (United Kindgom). Dept. of Chemistry

This paper presents calculated properties of normal and inverse spinel structures of MgAl{sub 2}O{sub 4} and of point defects in the spinel structure. These results provide information for further study of possible metastable states. Calculated properties of ``amorphous`` structure are also presented. Atomistic simulations show that in MgAl{sub 2}O{sub 4} spinel structure, the exchange of an Mg{sup 2+} ion with an Al{sup 3+} ion has the lowest energy increase, 0. 92eV/atom. The Schottky defect increases the energy by 3.71 eV/atom. Frenkel defects are difficult to form, increasing the energy at least 4.59eV/atom for the Mg{sup 2+} Frenkel defect. Proposed rock salt structure of MgAl{sub 2}O{sub 4} has smaller volume and larger Young modulus, and the amorphosu state has larger volume and smaller Young modulus than the MgAl{sub 2}O{sub 4} spinel.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 93980
• Report Number(s): LA-UR--95-1650; CONF-9505249--3; ON: DE95015331
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINATES
AMORPHOUS STATE
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
MAGNESIUM COMPOUNDS
METASTABLE STATES
PHYSICAL PROPERTIES
SPINELS