In January 1848, Wilhelm Weber published his related work in Poggendorff's Annalen. Weber was a key figure in both the experimental and theoretical understanding of diamagnetism, extending Ampère's theory to cover diamagnetism, arguing that it is caused when resistanceless molecular currents are induced in diamagnetic substances. His lasting impression on physical theory was his atomistic conception of electric charge and its role in determining the electrical, magnetic and thermal properties of matter. 32 In this paper, 33 Weber raised the question of action at a distance, saying ‘were we to admit that the diamagnetic force has its origin in the unvarying metallic particles of the bismuth itself,…it would be the first case in which the action of a ponderable upon an imponderable body [meaning magnetic fluids] at a distance had been observed’. Weber in this paper was explaining the effect of opposite magnetic poles on the same side of a piece of bismuth, which is subtractive not additive, 34 as due to distribution of the ‘imponderable constituents’ i.e. north and south magnetic fluids, and that on Ampère's theory currents induced in diamagnetics are in the contrary direction (whereas in magnetics they would be in the same direction), as Faraday had pointed out. 35 So, ‘if the two magnetic fluids, or their equivalents, Ampère's currents, are really present in the diamagnetic bodies, which are set in motion or rotated under the influence of a powerful magnet, they must induce an electric current in a neighbouring conductor at the moment this change takes place’. Weber designed experiments to observe these induced currents and to show that those induced in bismuth are opposite to those in iron. He explained that the molecular currents exist in iron independently of any external excitation, whereas those in bismuth are entirely induced.
A paper on Weber's Electrodynamics applied to gravity, which involves discussing how Weber thought there was a rotational frame relation between the sample body and the reference frame for the remainder of the universe (action at a distance): [https://www.jamespaulwesley.org/Document_Files/Weber_Electrodynamics_Part_III_Mechanics_Gravitation_JP-Wesl
... keep reading on reddit ➡Hey! I’m currently taking up a class in university chemistry. I’m genuinely curious, is the definition of paramagnetism and diamagnetism a bit problematic?
From definition, paramagnetic substances are those with unpaired electrons. The opposite goes with diamagnetic substances, whose electrons are all paired.
I see that some elements follow this, like Manganese for example. It contains unpaired electrons and is thus paramagnetic. Why is it though that other elements don’t follow this “rule”? Such as calcium. If you draw its orbital diagram all electrons are paired but a quick Google search would show that it is actually paramagnetic and not diamagnetic.
So yeah, now I’m just confused. I’m not sure whether or not an element is paramagnetic or diamagnetic even after I’ve drawn their orbital diagrams.
I’m sorry if this question will strike a nerve with people, I just really don’t understand. Thanks!
Why are diamagnetic materials repulsed by an external magnetic field? Materials with an unpaired electron are said to be paramagnetic while those who don't possess an unpaired electron are said to be diamagnetic. My current understanding is that the magnetic torque generated by the electron spin in paired electron orbitals cancel each other out and thus there is no net magnetic torque generated whereas the unpaired electron has a net magnetic torque. If there is no net magnetic torque, why will the diamagnetic material be repulsed by an external magnetic field?
My chemistry lecturer then said that in addition to the magnetic torque generated by spin, there is an orbital angular momentum which generates the magnetic field and that accounts for why diamagnetic materials are repulsed by an external magnetic field. But I thought that the Rutherford model is wrong: electrons do not have determined paths. Even Griffith's Introduction to electrodynamics describes electrons as revolving around the nucleus. What accounts for the repulsion in diamagnetic materials then? Why does the induced dipole moment in diamagnetic materials point in the opposite direction of the external magnetic field?
Finally, why do ferromagnetic materials retain their magnetism even after the external magnetic field has been removed? Both ferromagnetic and paramagnetic materials have unpaired electrons but very different behaviour.
I was recently reading an article about diamagnetic levitation where multiple objects and even a frog were levitating above a magnetic field of 16 Teslas. It included a mathematical explanation as to how to calculate the intesity of field required for any given body, though I goes far beyond my level of physics. I'd love if anyone could give an estimation about the strength of the field needed for, lets say, a human boy of 175cm and 70kg, in all regular conditions on earth surface. (I'd truly appreciate all the calculus process if possible)
Here's the article: http://www.ru.nl/hfml/research/levitation/diamagnetic/
Studying I just learned that there’s things that magnets exclusively repel called diamagnets, but I’ve never seen on in real life, not even in college labs when studying magnetism. From what I’ve seen online diamagnetic materials are barely repelled in comparison to strong magnets attracting paramagnetic material which can crush fingers, why is this the case?
The diamagnetism of water is weak, but I've heard of Magneto pull a planet-killing bullet out of its flight path and to nearly the speed of light. Tearing a human apart would be easy in comparison. But I haven't heard much about that. Is that something he can do? Could he alternate a magnetic field and microwave someone to death?
This is probably a silly question, but I haven't found an answer to it. How does diamagnetism work from a quantum view? I did the derivation in class where we assumed nice orbits where the current is affected by a changing field. But in reality, the electrons aren't really moving. They are in a superposition of states, otherwise bremsstrahlung would cause them to fall into the nucleus. So how does diamagnetism work?
I know this is all simplified, but I am curious how others view this.
Paramagnetism is exhibited when there are unpaired electrons shells, meaning that you have electrons that want to pair. However, some materials are more paramagnetic than others. Gadolinium 3+ is used in MRI because it can be highly paramagnetic, but what makes it better than other lanthanides in the series? Is it that there's an unpaired d electron?
An idea I had of using diamagnets to contain samples of antimatter.
For those of you who haven't heard of them before, a diamagnet is a material that, when exposed to a magnetic field, will generate a magnetic field in opposition to the applied field. In short, it's something that will repel off of magnetic fields.
The idea goes something like this:
- A charged or magnetic sample of antimatter is surrounded by a shell of diamagnetic matter
- It can work at both nanoscale (with charged ions) and macroscale (with magnets made out of antimatter)
- For preference, the diamagnetic material should be a room-temperature superconductor
- If the sample is charged, it needs to have space to move inside its container
- A moving charge generates a magnetic field around itself. A magnetic sample is already magnetic.
- The magnetic field of the sample induces an opposing magnetic field in the diamagnetic container
- The opposing field pushes the sample away from the wall of the container, preventing contact between matter and antimatter
- Go back to step 3
This method doesn't need an external power supply to contain the antimatter, so it can't run out of battery and explode. It also scales up to macroscale samples of antimatter, allowing for bulk storage.
There are a few disadvantages to this method:
- For nanoscale storage of antimatter, there is the problem of finding a substance that is diamagnetic at those scales
- The container needs to be solid enough that it can't be pierced. If the container is pierced, the atmosphere will rush inside and annihilate the antimatter.
- If too large of a force is applied to the container, then it will overcome the repulsion between the walls and the antimatter, causing the antimatter to be annihilated. The exact force needed to do this would depend on the size of the sample and how strongly diamagnetic the container is.
