An Introduction to Neutron Scattering - Spallation Neutron Source

~650Å
~1350Å
Reflectivity
Non-Fickian Boron Self-Diffusion at an Interface*
10
0.1
0.001
10 -5
10 -7
10 -9
10 -11
0 0.02 0.04 0.06 0.08 0.1 0.12
11 B
10 B
Si
Boron Self Diffusion
Q (Å -1
)
Unnanealed sample
2.4 Hours
5.4 Hours
9.7 Hours
22.3 Hours
35.4 Hours
*Data courtesy of G. Smith (LANSCE)
-2 )
Scattering Length Density (Å
8 10 -6
7 10 -6
6 10 -6
5 10 -6
4 10 -6
3 10 -6
2 10 -6
1 10 -6
Non-Standard Fickian Model
10 -4
10 -5
10 -6
10 -7
10 -8
10 -9
10 -10
10 -11
Data requires density
step at interface
0
-800 -600 -400 -200 0 200 400 600 800
Distance from
11 B- 10 B Interface (Å)
0.045 0.05 0.055 0.06 0.065 0.07 0.075 0.08
-2 )
Scattering Length Density (Å
8 10 -6
7 10 -6
6 10 -6
5 10 -6
4 10 -6
3 10 -6
2 10 -6
1 10 -6
Fickian diffusion
doesn’t fit the data
Standard Fickian Model
0
-600 -400 -200 0 200 400 600 800
Distance from
11 B- 10 B Interface (Å)