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Toward Microscopy with Direct Electronic, Chemical and Magnetic Contrast at the Atomic Level

December 5, 2012 4:00PM to 5:00PM
Presenter 
Volker Rose (XSD), Physicist
Location 
Building 440, Room A105-106
Type 
Colloquium
Series 
CNM Nanoscience Colloquium
Refreshments will be available at 3:30 p.m.

Abstract:
In this talk we will discuss the development of a novel high-resolution microscopy technique for imaging of nanoscale materials with chemical, electronic, and magnetic contrast [1,2]. It will combine the sub-nanometer spatial resolution of scanning tunneling microscopy (STM) with the chemical, electronic, and magnetic sensitivity of synchrotron radiation [3]. Drawing upon experience from a prototype that has been developed to demonstrate general feasibility, current work has the goal to drastically increase the spatial resolution of existing state-of-the-art x-ray microscopy from only tens of nanometers down to atomic resolution.

Key enabler for high resolution is the development of insulator-coated “smart tips” with small conducting apex [4]. After entirely coating of a sharp PtIr tip with an insulating SiO2 film by electron beam physical vapor deposition, the insulating film has been removed from the apex by means of high-resolution focused ion beam milling using a shadow masking technique. Such tips drastically reduce the background of photoejected electrons that would otherwise cause an undesired signal at the sidewall of the tip.

The novel microcopy technique will enable fundamentally new methods of characterization, which will be applied to the study of energy materials and nanoscale magnetic systems. A better understanding of these phenomena at the nanoscale has great potential to improve the conversion efficiency of quantum energy devices and lead to advances in future data storage applications.

References:
[1] V. Rose, J.W. Freeland, S.K. Streiffer, “New Capabilities at the Interface of X-rays and Scanning Tunneling Microscopy”, in Scanning Probe Microscopy of Functional Materials: Nanoscale Imaging and Spectroscopy, S.V. Kalinin, A. Gruverman, (Eds.), Springer, New York (2011), pg 405-432.

[2] M.L. Cummings, T.Y. Chien, C. Preissner, V. Madhavan, D. Diesing, M. Bode, J.W. Freeland, V. Rose, Ultramicroscopy 112, 22 (2012).

[3] V. Rose, T.Y. Chien, J.W. Freeland, D. Rosenmann, J. Hiller, V. Metlushko, J. Appl. Phys. 111, 07E304 (2012).

[4] V. Rose, T.Y. Chien, J. Hiller, D. Rosenmann, R.P. Winarski, Appl. Phys. Lett. 99, 173102 (2011).