Intellectual Merit: New Technology

Gary J. Mankey, University of Alabama Tuscaloosa, DMR 0821704

Extensive interaction with the CVD Equipment Corporation has resulted in a new design that meets all of our process requirements. The Chemical Vapor Deposition (CVD) system will be connected directly to the Pulsed Laser Deposition (PLD) system through a gate valve. Loading of precursors into the CVD tube is accomplished through a load lock door opposite the gate valve. This is a new design that enables rapid exchange of samples between the process chambers to maintain the integrity of the interfaces between the materials deposited and structured with the two deposition techniques. The simplicity of the design insures consistent, reliable operation that is user-friendly.

Schematic of CVD system and interface to the PLD vacuum chamber.

Broader Impacts: Educational Benefit

Gary J. Mankey, University of Alabama Tuscaloosa, DMR 0821704

Two undergraduate students, Robert Garcia and Boyang Li, and one graduate student, Xing Zhong, are involved with this project. Mr. Garcia is a mechanical engineering student assisting with the design and implementation of the vacuum transfer system from PLD to CVD. Mr. Li and Mr. Zhong are learning to optimize the low-pressure CVD process for synthesizing ferromagnetic CrO2 using a home-built bench top system. The XMCD spectra in the figure show that the low-pressure films are not yet optimized and give a lower moment than the atmospheric pressure CVD. Learning to optimize the process further with the turn-key commercial CVD system will enable the students to form conformal ferromagnetic coatings on nanostructures.

Comparison of x-ray magnetic circular dichroism (XMCD) spectra for atmospheric pressure (AP) and low pressure (LP) CVD CrO2 films. Our initial results on the LP films indicate that the magnetic moment is lower than that of AP films.