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Analysis of Phase Separation in Czochralski Grown Single Crystal IlmeniteIlmenite (FeTiOs) is a wide bandgap semiconductor with an energy gap of 2.58 eV. Ilmenite has properties suited for radiation tolerant applications, as well as a variety of other electronic applications. Single crystal ilmenite has been grown from the melt using the Czochralski method. Growth conditions have a profound effect on the microstructure of the samples. Here we present data from a variety of analytical techniques which indicate that some grown crystals exhibit distinct phase separation during growth. This phase separation is apparent for both post-growth annealed and unannealed samples. Under optical microscopy, there appear two distinct areas forming a matrix with an array of dots on order of 5 pm diameter. While appearing bright in the optical micrograph, atomic force microscope (AFM) shows the dots to be shallow pits on the surface. Magnetic force microscope (MFM) shows the dots to be magnetic. Phase identification via electron microprobe analysis (EMPA) indicates two major phases in the unannealed samples and four in the annealed samples, where the dots appear to be almost pure iron. This is consistent with micrographs taken with a scanning probe microscope used in the magnetic force mode. Samples that do not exhibit the phase separation have little or no discernible magnetic structure detectable by the MFM.
Document ID
20000032224
Acquisition Source
Headquarters
Document Type
Conference Paper
Authors
Wilkins, R.
(Prairie View Agricultural and Mechanical Coll. TX United States)
Powell, Kirk St. A.
(Prairie View Agricultural and Mechanical Coll. TX United States)
Loregnard, Kieron R.
(Prairie View Agricultural and Mechanical Coll. TX United States)
Lin, Sy-Chyi
(Prairie View Agricultural and Mechanical Coll. TX United States)
Muthusami, Jayakumar
(Texas A&M Univ. College Station, TX United States)
Zhou, Feng
(Texas A&M Univ. College Station, TX United States)
Pandey, R. K.
(Texas A&M Univ. College Station, TX United States)
Brown, Geoff
(Los Alamos National Lab. NM United States)
Hawley, M. E.
(Los Alamos National Lab. NM United States)
Date Acquired
August 19, 2013
Publication Date
February 22, 1998
Publication Information
Publication: NASA University Research Centers Technical Advances in Aeronautics, Space Sciences and Technology, Earth Systems Sciences, Global Hydrology, and Education
Volume: 2 and 3
Subject Category
Solid-State Physics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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