BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Nano-mechanics: Atom resolved AFM and Nanoimprint Lithography - J.
 B.Pethica\, Trinity College Dublin\, Ireland
DTSTART:20070202T153000Z
DTEND:20070202T163000Z
UID:TALK6438@talks.cam.ac.uk
CONTACT:spl37
DESCRIPTION:This talk will describe two new experimental areas in Nano-mec
 hanics.\nRecent improvements in signal to noise for small (&lt\;0.05nm) am
 plitude AFM\nnow enable routine recording of force gradient and tunnel cur
 rent simultaneously at\natomic resolution. This eliminates the uncertainty
  of position between force and current\nwhich arises in separate imaging. 
 Results for Si(111)\, TiO2(110) and Cu(100) surfaces\nwill be shown. Compa
 rison of constant height and constant current images shows that\nlocal ele
 ctrostatic forces may be substantial even for Si\, and that long range for
 ces are\nless significant than previously thought. For oxides\, the polari
 ty of the tip can be\ndetermined directly from the registry (anion vs cati
 on) between force and current\, giving\na potentially powerful new local c
 harge sensing method.\nImprint lithography(the formation of patterns by me
 chanical stamping into a soft\nmaterial) has nanometre resolution\, high t
 hroughput and low cost. We have used nanoindentation\nmethods to understan
 d the residual film and hence mask ratio limitations of\nnormal loading. t
 hese are mainly due to elastic strains. It will be shown that a small\namp
 litude shear oscillation provides a remarkable increase in mass transport\
 , preserves\nfull nm fidelity and has important scaling advantages in manu
 facture. Finite element\nmodelling clarifies the novel inelastic pumping m
 echanism involved\, and the surprising\nrelative insensitivity to interfac
 ial friction conditions.
LOCATION: IRC in Superconductivity Seminar room
END:VEVENT
END:VCALENDAR