Can Ferromagnetism Be Proven in Trapped Air?

In summary, the conversation discusses the possibility of saturating an air core and whether air can be considered a magnetic material. Some participants argue that air is not magnetic, while others mention research that suggests air can exhibit ferromagnetism. The concept of non-magnetic materials is also brought up, with the idea that all materials exist on a spectrum between conductors and insulators. The conversation ends with a discussion on the proof of ferromagnetism and the limitations of current models.
  • #1
Pythagorean
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Is it possible to saturate an air core? Would you have to trap the air for this to work. Are domains a meaningless concept in a fluid, even if it's trapped? (i.e. it can still circulate in it's 'prison').
 
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  • #2
Pythagorean said:
Is it possible to saturate an air core? Would you have to trap the air for this to work. Are domains a meaningless concept in a fluid, even if it's trapped? (i.e. it can still circulate in it's 'prison').

I don't believe you can talk about saturation unless the core is ferromagnetic in nature. Not sure about paramagnetic and diamagnetic materials, but AFAIK, air is not magnetic.
 
  • #3
berkeman said:
I don't believe you can talk about saturation unless the core is ferromagnetic in nature. Not sure about paramagnetic and diamagnetic materials, but AFAIK, air is not magnetic.

but are any materials truly non-magnetic?

I've always had this kind of philosophy (not assuming that it's correct, but it's my working philosophy for now) that there are no absolutes in nature. As an example, there's no perfect conductors or perfect insulators... everything is somewhere in between.

Note: I'm a hybrid physicist-engineer, so I tend to get completely different answers depending on which flavor of professor I ask these questions.
 
  • #4
I believe that you will measure the same inductance whether an "air core" inductor is in air or in a vacuum, but I haven't tried the experiment.

As for non-magnetic materials I'm thinking now about large MRI magnets and Fusion confinement magnets... Seems like the air around them (well, until the Fusion chamber is pumped down) isn't disturbed by those high fields. Interesting question, though.
 
  • #5
berkeman said:
I don't believe you can talk about saturation unless the core is ferromagnetic in nature. Not sure about paramagnetic and diamagnetic materials, but AFAIK, air is not magnetic.
This gas is ferromagnetic. See
www.bit.ly/119g0V
or
http://www.sciencemag.org/cgi/content/full/sci;325/5947/1521
Bob S
 
  • #6
Bob S said:
This gas is ferromagnetic. See
www.bit.ly/119g0V
or
http://www.sciencemag.org/cgi/content/full/sci;325/5947/1521
Bob S

Wait a minute... so ferromagnetism hasn't been proven yet?!

Good find.

edit: nevermind, poor wording:

"Ketterle and company weren't able to spot individual domains of alignment, which would be incontrovertible proof of ferromagnetism"

I'm guessing ferromagnetism is the observation, and this sentence is trying to say that there's no proof that Stoner's model necessarily leads to that observation.
 

1. How does air core saturation work?

Air core saturation is a process in which a magnetic field is applied to a coil, causing the air inside the coil to become magnetized. This creates an inductance effect, allowing the coil to store energy in the form of a magnetic field.

2. What are the benefits of using air core saturation?

One of the main benefits of air core saturation is its ability to store energy without the need for a physical core material. This reduces the size and weight of the coil and also eliminates the possibility of core saturation, which can limit the performance of traditional magnetic cores.

3. Can air core saturation be used in all types of coils?

No, air core saturation is typically only used in coils that require high frequency operation, such as radio frequency (RF) coils. This is because the air core has a lower inductance value compared to traditional magnetic cores, making it more suitable for high frequency applications.

4. Are there any limitations to using air core saturation?

One limitation of air core saturation is its lower inductance value compared to traditional magnetic cores. This can result in decreased efficiency and performance in certain applications. Air core saturation also tends to be more sensitive to external magnetic fields, which can cause interference and affect the accuracy of the coil.

5. How is air core saturation different from other types of core materials?

Air core saturation is different from other types of core materials because it does not use a physical core to store energy. Instead, it relies on the air inside the coil to become magnetized. This eliminates the need for a physical core, making the coil smaller, lighter, and more efficient for certain applications.

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