Stanford Synchrotron Radiation Laboratory More Thin Film X-ray Scattering: Polycrystalline Films Mike Toney, SSRL 1. Introduction (real space – reciprocal space) 2. Some general aspects of thin film scattering 3. Polycrystalline film (no texture) – RuPt 4. Some texture film - MnPt 5.Summary • how do you get diffraction data from thin films 20 nm 10x (11L) (02L) (12L) (20L) (21L) (13L) (22L) (14L) (23L) (31L) (24L) 20 nm 10x (11L) (02L) (12L) (20L) (21L) (13L) (22L) (14L) (23L) (31L) (24L)
36
Embed
Stanford Synchrotron Radiation Laboratory More Thin Film X-ray Scattering: Polycrystalline Films Mike Toney, SSRL 1.Introduction (real space – reciprocal.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Stanford Synchrotron Radiation Laboratory
More Thin Film X-ray Scattering: Polycrystalline Films
Mike Toney, SSRL
1. Introduction (real space – reciprocal space)2. Some general aspects of thin film scattering3. Polycrystalline film (no texture) – RuPt4. Some texture film - MnPt5. Summary
• how do you get diffraction data from thin films• how to choose what to do (what beam line & scans)• what do you learn
•what beam line? (2-1, 7-2, 11-3)• area vs point detector, nature of sample• energy & flux
•what scans? (“where” in reciprocal space)• what do you want to learn?• what kind of sample (epitaxial, textured)? phase identification lattice parameters defects texture crystallite size atomic structure
Calculate S from (110)/(220)intensity ratio:S = A[I(110)/(fPt-fMn)2]/[I(220)/(fPt+fMn)2]I = integrated intensity of peaksA = Q dependent termf = atomic form factor
fc c (2 2 0 )
(2 2 0 )
(2 0 2 )(11 0 )
(0 0 1 )
(111 )
(11 0 )(2 0 0 )
(0 0 2 )
S=1/2
Calculate fcc & L10 fraction form fcc(220) and L10 (220)/(202):fcc fraction = B*I(fcc)/[I(fcc) + I(L10)]B is Q dependent term close to 1.0
S=0 S=1
Cebollada, Farrow & Toney, in Magnetic Nanostructures, Nalaw, ed. 2002
• Scan choice requires knowledge of reciprocal space & what you want to learn
(111)
(110) (220)
(111)
(200)
thin MnPt remains fcc => not antiferromagnetic and no exchange biascoexistence between fcc and L10 (inhomogeneous) need complete L10 order to get highest exchange grain growth and change in preferred orientation with development of chemical order