Magnetic Science and Technology Microanalysis Laboratory

1. Magnetic Science and TechnologyMicroanalysis Laboratory Summer 2003

2. Microscopy/Analysis of Metal Oxide Thin Films Jennifer Haid Fairview Middle School 6th Grade Science Jo Anne McBrearty Hawks Rise Elementary School 5th Grade

3. What is a Metal Oxide Thin Film? • It is a material grown on a substrate, which contains a transition metal, a group II and/or III element, and oxygen. • Type of ceramic

4. Purpose of Metal Oxide Thin Film Research: • Discover new and different properties of inorganic transition metal oxides • These properties may eventually be utilized in device applications: • High critical temperature superconductors • construct magnets, maglev trains, reduce energy costs, microscopic circuitry • Colossal magnetoresistance (huge magnetic field resistance) in the manganites. • Utilized in read-heads in computers

5. What Metal Oxides are Being Researched? • Ca2RuO4 (calcium ruthenate oxide) is the current focus • Properties: Paramagnetism, transitions between a conductor to insulator at very low temperatures • Lanthanum doped Ca2RuO4(lanthanum replaces small amount of calcium, Ca2-XLaXRuO4) • New properties: Weak ferromagnetism, conducting metal Paramagnetism: disoriented electron spins; must apply a magnetic force for it to have magnetic properties Ferromagnetism: aligned electron spins

6. Ultimate Goal: • Grow a film that is triple layered: • These layered metal oxides may have new properties: • Colossal magnetoresistence • Stronger ferromagnetism Ca2-XLaXRuO4 Ca2RuO4 Ca2-XLaXRuO4

7. Research Equipment: • Optical Microscope • ESEM (Environmental Scanning Electron Microscope) • Energy Dispersive X-ray Detector (detects element composition) • X-ray Diffraction Machine • TEM (Transmission Electron Microscope) • Hydraulic Pressure Machine • SQUID (Super Conducting Quantum Interference Device) • Pulsed Laser Deposition

8. Optical Microscope: Microscope utilizing white light as its illumination source, allows up to 1,000X magnification • Uses: • Observe sample at lower magnifications • Prepare thin film samples under this microscope, because the microscopic nature of the thin film

9. ESEMEnvironmental Scanning Electron Microscope: Microscope utilizing electrons as the illumination source, allows up to 300,000X magnification Use: Observe the surface features of samples in greater detail, better resolution

10. TEMTransmission Electron Microscope: Microscope utilizing electrons as the illumination source, allows up to 1,500,000X magnification • Uses: • Observe the inside of a sample • (thin cross section) • 2) Observe atomic layer stacking High Resolution of TEM image of MgO crystal

11. Microscope Comparisons

12. X-ray Diffraction Machine • Uses X-ray diffraction to confirm the structure of targets and thin films

13. Energy Dispersive X-ray Detector (detects element composition) • - Attached to the ESEM and TEM • Use: • Creates a spectrum which gives the following information: • Element composition of • the sample • Quantities of each element detected

14. Hydraulic Pressure Machine Use: to compress the powder form of the chemicals in order to make the target 5 tons of pressure was being applied to this sample!

15. SQUID (Super Conducting Quantum Interference Device) • Measure magnetic properties of a sample - uses liquid Helium to test a wide range of temperatures SQUID Cube Liquid Helium Tank

16. Pulsed Laser Deposition • The laser beam is directed to the target, causing ions of the desired film to jump off in a plume. The ions in the plume hit the substrate, and a thin film grows upon this substrate. KrF laser

17. Observing Laser Deposition

18. Scientific Method is applied in the Thin Film Development! • Prepare sample • Gather data • Analyze data/Understand/Draw conclusions

19. Growth of Thin Film(preparation of sample): • Make target by compressing the desired chemical compound for film and heat to 880°C • Use X-ray diffraction on target to be sure the structure is correct • Pulsed Laser hits target, ions jump off in a plume • Plume hits substrate and ions are deposited and grow to make a thin film

20. Characterization of Thin Film (gathering data): • Use ESEM, Energy Dispersive X-ray Detector (element composition) and X-ray Diffraction (structure) to confirm characteristics of film • Use TEM to investigate microstructures inside film, the stacking of atomic layers

21. Physical Properties Measurement of Thin Film (gathering more data): • Measure magnetic property using SQUID (Super conducting quantum interference device) • Resistivity measurement

22. Analyze Data/Understand/Draw Conclusions • A work in progress…

23. New Questions/ Problems Arise While Conducting Research • CaO was used in making a target. The target was not confirmed to be the desired material…why? It was suspected that the CaO may have been exposed to water, making the target incorrect. We tested the CaO and did indeed find out, water had gotten into the chemical and may have changed it to Ca(OH)2

24. Special Thanks: • Dr. Yan Xin • Mr. Xu Wang

25. Thanks: • National High Magnetic Field Laboratory • National Science Foundation • Center for Integrating Research and Learning • Dr. Pat Dixon, Director CIRL • Ms. Gina LaFrazza-Hickey,Education Specialist CIRL • Dr. Jack Crow