Magnetism : the force that can be felt but not seen.
Magnetism is a property of a material, caused by electron states. It can change depending on ambient conditions. Some materials, like nickel and cobalt, are nearly always magnetic (having unpaired electrons). Other materials can have induced properties of magnetism by being in an electromagnetic field. There are also dynamic properties of magnetism occurring with special pulses or during geologic formation processes. Let’s see exactly what magnetism is caused by.
Ultimately all the different kinds of magnetism come down to the same thing. Magnetism is a result of instability in the electron behavior. This comes from incomplete valence bands (outer electron cloud), where unpaired electrons may change spin in response to a magnetic field.
The valence band determines the reactive potential of the atom or compound. Noble gases represent a class of elements that have full valence shells, and therefore have stable states, and are nonreactive. Metals more readily magnetize and unmagnetize because the conduction band electrons have a bit more “freedom”.
Magnetic metals can also be in the form of ferro-fluids, particles suspended in fluids or gels. Any suspended ions or particles with a dipole moment essentially give the fluid magnetic properties. This is just good to keep in mind since biologically everything is in a dielectric.
What is magnetism caused by?
“Magnetic spins states” are what the electrons do collectively to set up a magnetic field, by way of the “directionality” (net polarization) of their energy. The potential for the direction to be pointing one way or another is what allows the field to deviate from a net zero effect (balanced, arising from the sum of many random directions).
Magnetic fields are always a byproduct of any electric fields as well, but those may as well be negligible as they are generally very weak in proportional to the electric fields we generally experience. This also has to do with the directionality of electromagnetic fields. An electromagnetic field always has an electric component and a magnetic component, and these components are perpendicular, or orthogonal (normal) to one another. So when the electric field is in a certain plane, the magnetic field wraps around it. (Determined by the “right hand rule” for cross products in physics.)
The magnetic material sets up a magnetic field around it, causing a physical force on items at a distance. The mysteries of magnetism leads to moving things at a distance in a telekinetic type way. Superconductors are a really good example of magnetic force, levitating lightweight discs with no friction at all.
This is a nonlinear magnetic effect that only shows up when the material is below normal temperatures. Now here is all about how the electrons, either paired or unpaired, results in magnetism.
Electron States determine Magnetic Properties
Magnetism comes from the fluctuations in spin states of electrons in a material. When the electron spin states change to stabilize, a magnetic flux or magnetic moment forms. “Flux” just means a change in, like a fluctuation. The “moment” is the ability to enact work, having stored energy. The flux sets up a temporary magnetic field. In a configuration where overall the states are “pointing a particular direction” from the bulk material, then the material is magnetic, the ability to to work is within the electron states on a zoomed out level.
The magnetic field is the orthogonal component of an electric field, that when has enough strength and directionality can enact a tangible force. The force is always physical, but not always able to move things, beyond some small iron dust bunnies. When conditions are just right the magnetic force can make a big difference, and this is normally engineered, like in the superconductor above.
Magnetism is caused by the spin states, but where do the spin states come from?
Spin states come down to statistical probability mixed with a sort of “prior history” of magnetic fields the electrons have been in. We can generally know how the electrons of a bulk material will behave, especially if we “tune” it in a magnetic field. For example, lodestone is relatively easy to magnetize by applying a field. Then the electrons are all oriented the same way.
But the smaller and smaller the pieces get, the less the statistical interpretation will matter, and the more so the quantum randomness may play a role. This is the case of smaller than nano-sized particles (usually between 10-10000 atoms). We also have more pronounced magnetic effects on the surface than in the bulk of materials. Surface effects lead to those nano-sized situations having a strong effect and emphasis. Non-linear and geometry-determined surface effects then overwhelm the “bulk”.
How Electron Orbitals Work
The periodic table tells you the number of electrons in each neutral element. For example, hydrogen is 1, carbon is 6, and oxygen is 16. As you count up electrons, they “fill out” the energy clouds (electron orbitals) around the nucleus in a very certain way.
The electrons invariably do this a very certain way unless there is an outside factor. The atom wants to be STABLE, that’s what makes it an atom and not just raw energy. So the electrons make certain “agreements” with each other about how each will behave, so they can happily live there together.
The “behavior” determining magnetism is the spin states referenced. This is a quantum mechanical property, and I put a PDF at the notes if you want to see the quantum mechanical derivation of the spin state “rules”. They are essentially equations showing “stable states.”
In the notes there is also a link to see the exact orbitals made from mathematical models. Knowing the electron configurations of elements, molecules, and compounds can assist in making predictions about the ways in which certain substances will react or not and how, and what substances will form.
Electron configurations can also predict stability. An atom is most stable (and therefore unreactive) when all its orbitals are full. The most stable configurations are the ones that have full energy levels. These configurations occur in the noble gases. The noble gases are very stable elements that do not react easily with any other elements.
Chemistry Terms Related to Magnetism
Hund’s Rule
Hund’s rule just states that every atomic orbital (cloud level) within a sublevel is singly occupied before it is doubly occupied. This is typically represented by each cloud level having a number of slots.
The slots must fill with one electron for each and every slot, then they can double up. This keeps the energy stable. Total spin value maximizes when it’s all singly occupied, this is strong and stable. When we add ONE more electron to a fully singly occupied level, we get a lot of instability and reactivity.
Full valence materials are diamagnetic, which is not magnetic. Diamagnetic = locked in. Full shell = stable like noble gases.
Paramagnetism is when we have some unpaired electrons. The unpaired electrons can spin and interact with a magnetic field. Why? Electrons have negative charge, which repels each other.
Pauli Exclusion Principle
The Pauli exclusion principle says that those double filled slots spoken of above have the two electrons going OPPOSITE of one another. Electrons seek to minimize repulsion (energy stability.) In the dumbbell configuration, this is why the lobes spread as far as possible. It’s like holding the knots on two balloons together. After adding on top of the spherical s-shells, this is the best way to stabilize the energy, and that’s what the quantum mechanical equations show as well.
Remember the electrons are always moving about this cloud, on average marking out its surface. For the dumbbell, you can visualize the pair going in anti-parallel figure eights, and the spin-top shells are like the electrons “squirting” back and forth.
The Aufbau Principle is what people learn in school to determine the exact electron configurations and the precise symbolic representations. This is usually a row of boxes labelled with the orbital name (1s, 2s, 2p, etc) with arrows – one or two opposite arrows – filling the slots to represent occupation of the orbital. Another representation is the typed list, like 1s22s22p1, where the numbers tell how many electrons are in each orbital level.
Example: Elemental Carbon Electron Configuration
First you get the atomic number which is how many protons, neutrons, and electrons the element has in a base state. For carbon this is 6, so carbon has 6 electrons filling its clouds from 1s on up.
We start filling 1s which takes 2 electrons (opposite spin states). Then we have 4 left. The next orbital, 2s also takes two electrons, so we fill those and not have 2 more left for 2p. Written out, the electron configuration is 1s22s22p2. 2p has a maximum of 6 electrons (imagine three dumbbells held in the center bulging out and each can hold 2 electrons.) So carbon’s outer shell is not full (reactive). It will bond to things as one way to gain its full outer shell. Otherwise we could induce magnetism.
Zooming Out: Magnetic Domains & Dynamics
For magnetism in everyday life and bulk materials we have a net result from the magnetic domains. Some domains will win out and endow a net magnetic moment to the material. This net magnetic moment sets up a physical magnetic force field around the material.
As you can imagine it’s quite difficult to get all the electrons in agreement. The states are sensitive and introduced entropy, like any kind of heat, has a statistical probability to make the electron “go rogue”.
Critical phenomena in magnetic states are certain temperature, pressure, and other conditions that show where the magnetic properties change, on the boundary between stable states. This is where properties can go to zero or infinity. It looks like a “solid liquid gas” phase diagram but for magnetic states.
In general, the best magnetic properties come from very low temperatures and entropy, so all the electrons can stay on the same page. Iron however, because of its electron structure, is the best element for “permanent” magnetism. Usually for designs engineers just play off of known magnetic materials in different configurations.
Other Causes of Magnetism
While the past magnetic fields and structure of the material determines its magnetic properties, there are a few other ways to enact magnetism. The spin states can be changes by ambient effects, ambient fields, and turn nonmagnetic materials magnetic. Furthermore, the permanent magnets can lose magnetization. You can find phase transition charts for some elements, but more characterization is ongoing. We also have mathematical models looking for single molecule magnetizations.
Wonder no more of the miracles of magnets. Here at AbnormalWays I have also covered magnetic crystals in the brain. We have also listed out every type of magnetism that has been studied. Soon we are coving remanent magnetization, in which rock from Earth’s crust hold onto the magnetizations it received there.
Further Notes
This is a really good resource for the quantum mechanical description of magnetism plus orbital diagrams.
This has some good shapes on the different orbitals and why they stack like that.
More information on writing electron configurations.
