Propeller Head Plaza

Technical and scientific discussion of amps, cables and other topics.

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RE: So what's the deal with CD demagnetizers?

Posted by pictureguy on March 22, 2016 at 15:01:16:
First, you are assuming 'facts not in evidence' about all the other stuff which demagnetizing 'improves'.

As for thin aluminum? I've uesd various optical means to measure thickness, including what is called an Ellipsometer. I never DID figure out the (process dependent) index of refraction which would give me a reasonable answer. However, good results could be arrived at using something called a DekTak which basically drug a VERY tiny needle at VERY low 'tracking force' across a 'step' you could easily construct in an aluminum film.
I was primarily concerned with films from maybe 0.2 micron to 1.5 micron. The 'go to' device for measuring such films was called a '4-Point Probe' in which a current was forced thru 2 probeb and the VOLTAGE across the other 2 was measured. IF you know the 'Bulk Resistivity' of the material, it is an EASY machine calculation and yielded both consistant and repeatable results. ONCE you were calibrated to YOUR film.

A few other techniques are used, including X-Ray fluorescence and FTIR. (fourier transform-Infra red) Both of these require a long and detailed calibration process to make work. I worked with the X-Ray technique and to calibrate, had to send SAMPLES of known thickness to a lab for them to analyze. Even multiple layers can be done with this method. AS LONG AS you know a lot about some layers, you can determine UNKNOWN thickness. The lab took all my samples, some of multiple layers and sent me back the Measurement Files to plug into my system. What a PIA in a production envioronment.

My only fall back would be that molecules are polar in some fashion and the magnetic field somehow acts to align them which somehow effects the transmission of information THRU the effected 'thing' which than tickels your ears.

BTW, pure gold IS Very Slightly Manetic IN a magnetic field. Like perhaps, a demagnetizer.
Technically, gold is NOT paramagnetic, but rather Diamagnetic. But who cares?

One OTHER very interesting property of Gold is that it WILL pass a green light when in very thin sheets. Maybe only a couple hundred Angstroms.