Acoustomagnetic TPU / SEG calculation model

[MarkSnoswell]

Magnon - do you have a recommendation for Al, Ni and Ferrite powders to use?
I am set up for making composites and can fit this into my scheduled research program.

[Magnon]

Magnon - do you have a recommendation for Al, Ni and Ferrite powders to use?
I am set up for making composites and can fit this into my scheduled research program.

As you know, a very stable ( homogeneous ) magnetic field is needed to have a high Q.
Use very fine powder, that has very small grain size. When a small paramagnetic particel is in a stable magnetic field, there is not much eddy currents that can easily destroys this weak microwave emission from wobbled electron precession.
Al and ferrite is needed, but instead of Ni you can use some other magnetostrictive material. The highest known magnetostictive constant you can have with Terfenol-D.
If you use electrostriction for acoustic wave generation, you can use lead magnesuim niobate, that has a high electrostriction constant.
Or you can use ultrasonic transducer for acoustic wave input, like echosounder. For example 50 kHz and 200 kHz units are available, just find the right core dimensions that match with a frequency with a phonon calculator.
Instead of urethane or epoxy core base material, you can use some other dielectric and elastic material that has a good sound conductivity, like silicone rubber. You have to know / measure the sound speed in a core material, do a sample and measure how long time it takes for acoustic wave to travel through the sample. Because of the sound absorbtion in a electron-phonon coupling, the speed of sound is slightly decreased, that you must correct in a calculation.

--Magnon

[TechStuf]

http://www.youtube.com/watch?v=KX5jNnDMfxA


lol


TS

[Magnon]

With the SEG original magnets, there was a composite material used also, the powders was mixed with a dielectric thermoplastic. See the analysis about the materials.

http://oriharu.net/eseg1.htm

--Magnon

[Magnon]

@Mark,

You may find some interestig reading from here,

http://cat.inist.fr/?aModele=afficheN&cpsidt=1952570

http://www.iop.org/EJ/abstract/0038-5670/35/2/R03

http://www.ingentaconnect.com/content/maik/10637834/1999/00000041/00000002/00001228

http://cat.inist.fr/?aModele=afficheN&cpsidt=15884139

http://www.iop.org/EJ/abstract/0038-5670/19/6/R01

http://ulysses.phys.wvu.edu/~escime/miniconference/Shamrai.pdf


--Magnon