We seek to acquire an X-ray Photoelectron (XPS) / Auger Electron spectroscopy (AES) system for enhanced chemical characterization of surfaces and thin films. Specifically, we propose purchase of a PHOIBOS 100 hemispherical analyzer for charged particles (designed to work for XPS, AES, UPS, SAM, and ISS) and electron, X-ray, and UV sources from SPECS. The PHOIBOS 100 analyzer will allow us to study areas as small as 200 mm and carry out angle resolved and spatial resolved XPS and AES measurements. Since it has the possibility of working in multi channeltron mode (up to 9) this unit has very good energy resolution, 200 kcps @ 0.85 eV FWHM for Ag3d5/2 and 300 W Mg Ka in XPS mode and ultra high resolution of 4.4 meV on Ar 3p1/2 in UPS mode (He excitation). The PHOIBOS 100 analyzer, in combination with Scanning Electron gun (model EQ22/35), X-Ray Source (model XR-50), Ultraviolet Source (model UVS 10/35), and differentially pumped small-spot ion-gun (model IQE 12/38) will significantly expand our existing Molecular Beam Epitaxy system capability and will help us resolve important issues in understanding the correlations between chemical, structural and dynamic magnetic properties in multi-layered structures. In particular, we will investigate a series of problems which require very careful characterization of the chemical state of (mostly magnetic) elements at interfaces. For example, recently we have found that the rotational anisotropy in exchange bias systems (Fe/MnF2 and Fe/KNiF3) exhibit significantly different strength along the easy and hard axes of Fe ultrathin films. To understand the nature of this new effect we need to investigate the interaction between Fe atoms at the interface and antiferromagnets (MnF2 or KNiF3). The XPS technique is indispensable for such studies. Another interesting problem we would like to study is mixed valency of Eu atoms at the surface of the ultrathin EuF3 films and different Eu intermetallic compounds. This new instrumentation will significantly expand our research and teaching capabilities allowing us, together with students, to attack intriguing and important scientific problems.
The purchase of electron spectroscopy components for surface and thin film physics will significantly strengthen our teaching, basic research, and interaction between our department and local industry. The educational impact of this equipment on students is integrated in student participation in research as well as in specific courses such as advanced laboratory classes. Our laboratory offers a special opportunity for both undergraduate and graduate (M.S.) student training. By gaining laboratory expertise in both synthesis and measurements of thin films, students trained in our research group are well positioned to pursue careers in academia and in the Colorado semiconductor and magnetic storage industries. The proposed equipment will complement our existing facilities by allowing us to perform chemical characterization of materials along with the existing structural, magnetic and electrical characterization capabilities. Furthermore, we will be able to explore exciting issues of basic research such as understanding the correlations between chemical, structural and dynamic magnetic properties in multi-layered structures. In particular, we will investigate a series of problems which require very careful characterization of the chemical state of (mostly magnetic) elements at interfaces. Finally, this new equipment will allow us to collaborate more with small local R&D companies and help them to solve problems related to surface physics.
