Non-Metal Magnetism: Answers for a Curious Freshman

[rasgar]

I'm a freshman in college with only AP physics knowledge, and I'm curious about many aspects of physics. One of the thing that sparks my interest is magnetism and I was wondering if it is possible to have magnetic or electromagnetic force exerted on non-metals (maybe even noble gases). It would be nice if you go into the details such as what makes a magnetic particle magnetic (and why is it so exclusive that even liquid metals are not magnetic).

 

[Gokul43201]

Yes, it is possible to have non-metallic ferromagnets. As a common example, the ubiquitous magnetic tape of the 80s and 90s was made from the non-metallic chromium (IV) oxide. It is also predicted that at very high pressures, solid hydrogen possesses a ferromagnetic phase.

Ferromagnetism is not observed in liquids since it strongly depends on interatomic distances, which are much more closely fixed in a solid than in a liquid. In gases, the atoms are too far apart from each other to have ferromaggnetic overlap.

 

[rasgar]

Thank you for your response and I apologize for my erroneous post. I have a few more questions though. My first question is very sci-fi and hypothetical. Can a strong and controlled magnetic field influence electrons well enough to move objects such as plastic without chemically interacting with it (sort of like mechanic telepathy)? And even more far fetched, would it be possible to chemically engineer with it? Also can you use magnetism to cool down objects by lowering their thermal oscillations with the Doppler effect (similar to laser cooling), and if so, where would the energy go?

 

[f95toli]

First question: No

Second question: Not quite, but something called adiabatic demagnetization is used for refrigeration at low temperatures (below 4K).

Such fridges are made by e.g. CMR
http://www.cmr.uk.com

 

[rasgar]

Cool. I'd like to know why it's "no" for my first question though.

 

[Gokul43201]

If you ignore the recent advances in polyaniline-based ferromagnetic plastics, the answer is "no" because all (other) plastics (which are para/dia-magnetic) respond very, very weakly to magnetic fields.

 

[rasgar]

I didn't mean the electrons in a plastic molecule I meant free floating electrons guided by an electric field. Basically, I want to know if a really powerful magnet can act as a sort of substitute nucleus so that the electrons operate like a solid, whose strength is determined by the magnetic field.

 

[Gokul43201]

Unfortunately, your question in not physically meaningful, and you'll be hard-pressed to find a meaningful response to it...or perhaps, you're not being very clear in stating explicitly what situation you envision. It is thus difficult for us to respond.

 

[rasgar]

If you create an electromagnetic field that forces electrons to maintain a specific form, would it act as a solid, repelling the valence shells of other atoms without causing chemical reactions?

 

[Gokul43201]

If you create an electromagnetic field that forces electrons to maintain a specific form, would it act as a solid, repelling the valence shells of other atoms without causing chemical reactions?

At zero (or very, very low) temperautres and very large B-fields, the ground state of an electron plasma is something known as a Wigner crystal (i.e., the electrons form a lattice structure, just like the atoms in a crystal). This is essentially saying that an electron plasma can indeed be made to behave like a solid, under certain extreme conditions. However, if you perturb the plasma by bringing it into the vicinity of a real solid, then the plasma will be snapped out of its crystalline state.

 

[rasgar]

If it is snapped out of its state, can it still act as a liquid and manipulate other solids?