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Superconductor/Manganite Bilayer Thin Films in Cross Section. Isaac Brown 2003-04. Introduction. Smooth Cross Sections Materials Ceramic Superconductor: DyBa 2 Cu 3 O 7 Substrate: SrTiO 3 Manganite: La 2/3 Ba 1/3 MnO 3 Doped: LaMnO 3. Applications. •Electromagnets Power - PowerPoint PPT Presentation
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Superconductor/Manganite Bilayer Thin Films in Cross Section
Isaac Brown
2003-04
Introduction• Smooth Cross Sections
• Materials– Ceramic Superconductor: DyBa2Cu3O7
– Substrate: SrTiO3
– Manganite: La2/3Ba1/3MnO3
– Doped: LaMnO3
Applications•Electromagnets•Power
– Generation– Transportation
•Switching Devices
QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.
Method 1: Sandblaster
• Thinned substrate from the back with sandblaster
• Desired thickness after sandblasting: 50 µm
• Snapped thinned sample
Method 2: Polisher
• Polished fragment with diamond sandpaper
• Lubricated with– Water– Glycerol
Method 3: Microtome
• Embeded fragment in epoxy
• Cut off thin slices with glass knife
Measurements: AFM Height
• Measured height with an atomic force microscope
• Used 3 µm by 3 µm areas
• Took root mean squared
roughness readings on
full area and facets
• Desired value: 30 Å or less
Results: AFM Height
Results: AFM Height 2
Figure 5: Facet RMS
20
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30
32
34
Largest Smallest
Facets Ordered by Size
Facet RMS (Angstroms)
0
100
200
300
400
500
600
700
800
900
1000
Overall RMS (Angstroms)
FacetsOverall
Measurements: AFM Friction
• Took readings of relative friction so that different materials are distinctly visible
• Used to verify film quality and ability to be imaged
Results: Friction
Discussion: Facets
• Facet size does not affect facet RMS roughness
• Overall RMS roughness does not affect facet RMS roughness
• Facets are not arbitrary
Discussion: Methods
• Microtomy, using facets, was the smoothest usable method
• A film was imaged from only from one microtomy sample
• Epoxy and substrate should be minimized to protect film during microtomy
What Is Next?
• Scanning Tunneling Microscope– Spin-polarized current– Structure
• Supercondutor switching devices using the bilayer QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.
Acknowledgements
• Dr. Goldman
• Ms. Fruen
• Research class
• Everybody from the Goldman lab
Superconductor/Manganite Bilayer Thin Films in Cross Section
Isaac Brown
2003-04