High Voltage Electron Microscopy of Defects in Lithium Ferrite Spinel

Conference · Mon Mar 01 04:00:00 EST 1976

DOI:https://doi.org/10.1017/S042482010009186X· OSTI ID:7347917

Mishra, R. K. ^[1]

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1. Lawrence Berkeley Laboratory (LBL), Berkeley, CA (United States); University of California, Berkeley, CA (United States)

Ferrimagnetic oxide spinels are an important class of modern technological ceramic materials. These have long been recognized as being predominantly ionic in nature. Hornstra's crystallographic study of planar and line defects in spinel structure shows that dislocations of Burgers vector 1/2<110> can dissociate into two partials 1/2<110> = 1/4<110> + 1/4<110> bounding a cation stacking fault on {111} glide planes. These partials, in turn, can dissociate into quarter partials of Burgers vector 1/12<112> on {ill} planes, reducing strain energy and at the same time preserving electro neutrality through a synchroshear mechanism. The current paper describes experimental studies on the nature of the glide dislocations and their dissociation in lithium ferrite (inverse spinel) using high voltage transmission electron microscopy. High order bright field electron micrographs taken in the HVEM together with the computed image profiles implementing multibeam dynamical theory are used to determine the fault plane and estimate the stacking fault energy.

• Research Organization: University of California, Berkeley, CA (United States); Lawrence Berkeley Laboratory (LBL), Berkeley, CA (United States)
• Sponsoring Organization: US Energy Research and Development Administration (ERDA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 7347917
• Report Number(s): LBL--4977; CONF-760803-2
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure &amp; Phase Studies
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DEFORMATION
DISLOCATIONS
DISSOCIATION
ELECTRON MICROSCOPY
ENERGY
FERRIMAGNETIC MATERIALS
FERRITES
IRON COMPOUNDS
LINE DEFECTS
LITHIUM COMPOUNDS
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MAGNETIC MATERIALS
MICROSCOPY
MINERALS
OXIDES
OXYGEN COMPOUNDS
SPINELS
STACKING FAULTS
TRANSITION ELEMENT COMPOUNDS