Correia, TMTMCorreiaYoung, JSJSYoungWhatmore, RWRWWhatmoreScott, JFJFScottMathur, NDNDMathurZhang, QQZhang2014-05-122010-08-302014-05-122010-08-300003-6951http://hdl.handle.net/10044/1/13787Copyright © 2009 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Appl. Phys. Lett. 95, 182904 (2009) and may be found at http://dx.doi.org/10.1063/1.3257695Journal Articlehttp://dx.doi.org/10.1063/1.3257695