Superconductors.... (1 Viewer)

[inasero]

Ok having read through the first section of the chapter entitled 'semiconductors' (twice over) i have to say, what are they going on about? I am totally confused as to what diffraction grating is, why diffraction patterns are significant and applications in determination of crystal structures, etc etc....so would greatly appreciate if you could provide a brief summary of this section...in laymans terms of course

 

[underthesun]

I'm also quite curious whether diffraction gets that in-depth (to grating and that n,\ = d sin@ equation. I don't think the specimen paper from successOne covered such detailed stuff, but im still curious..

 

[PoLaRbEaR]

A diffraction grating is a tool consisting of thousands of closely spaced gooves used to separate the colours in a light source. It acts in the same way as if a light was shone through a prism, but is more finely detailed. An example of a diffraction grating is a CD, which, you should know, comprises of thousands of grooves, and when you shine white light on it you'll see the colours of the rainbow...
Diffraction patterns are used to determine the structure of the material. Electrons, neutrons or X-rays are used to bombard the material and create a diffraction pattern from the atoms inside. The angles at which they are diffracted is used to determine the position of atoms, and hence the structure of the material...[am i getting confused with the concept of neutron scattering..or is that the same thing?]

 

[+:: $i[Q]u3 ::+]

uhh... yep yep... neutron scattering with diffraction patterns has to do wit de wave nature of neutrons (de broglie)

you really don't need to know diffraction in too much detail inasero, so dont' get too confused =) mm... i think all u really need to know is that when light rays interact, or go through gratings, or around objects etc they make pretty patterns. And those pretty patterns can be analysed to figure out stuff about those holes or gratings or crystal or whatever.

 

[Constip8edSkunk]

hehe dun go as indepth as jacaranda goes... their explaination is pretty #$%#@ 2

but u only need 2 outline braggs experiment i think, and know they used diffraction patterns from bombardment of crystals by x-ray. by applicating braggs law and taking diffraction from various angles and faces, braggs jnr(i think it was) was able 2 work out the 3d structures. Just remember that the texts simplify the model as reflection of X rays on the various layers of crystal, but in reality the Xrays r diffracted, but the end result is similar to that of reflection. (ill give u the notes at school if u want)

 

[inasero]

thanks for clearing that up john....the explanation in jacaranda is fux0r3d....and i don't understand it....

but then again i dont understand braggs experiment either so any help again would be appreciated

 

[inasero]

btw happy birthday john!! i'll take a raincheck on those birthday punchees lol...can't wait to see u back at school~~

 

[pigs_can_fly]

lol inasero, i wonder why? knudge knudge wink wink

 

[Giant Lobster]

ahhh found it
the definitive guide to superconductivity::
http://www.ornl.gov/reports/m/ornlm3063r1/contents.html

 

[inasero]

greatly apprecaited i think i saw that in excel?

 

[mojako]

hehe dun go as indepth as jacaranda goes... their explaination is pretty #$%#@ 2

but u only need 2 outline braggs experiment i think, and know they used diffraction patterns from bombardment of crystals by x-ray. by applicating braggs law and taking diffraction from various angles and faces, braggs jnr(i think it was) was able 2 work out the 3d structures. Just remember that the texts simplify the model as reflection of X rays on the various layers of crystal, but in reality the Xrays r diffracted, but the end result is similar to that of reflection. (ill give u the notes at school if u want)

can you pls scan the notes for me?

in textbooks' diagram where the X-rays are reflected when they hit the planes of the crystal, do the reflected rays meet eventually? coz in the diagram they are in parallel, so won't meet and interfere....