All Types of Magnetism In the World (9+ Magnetisms)

These are ALL types of magnetism I could find, but rest assured there are more lurking in the nooks and crannies of science. For many niche kinds of magnetism, only the 10-20 people actively working in the field use the terms. A lot of magnetism jargon is just adopted for ease of clarity amongst researchers, driven by finding new effects. Basically ALL materials are diamagnetic or paramagnetic, so saying something is “magnetic” is simply too vague most of the time. You’ll find many types of magnetism overlap, while others are exclusive. Read on to read on.

What it Means to Be Magnetic

Magnetism comes from electron spin fluctuations, either changing direction locally or at large, adopting some kind of order, or losing some kind of order. All materials have some degree of magnetism even if it’s just one electron that got with the program. Strongly magnetic materials can talk atom to atom and all be on the same page. “Bulk magnetic susceptibility”, or just “susceptibility,” is a measure of ordinary magnetization that sums up each material by a value. The susceptibility is only a fixed value under controlled conditions. The magnetic susceptibility is essentially a measure of how easily the electrons can be pushed or pulled within their clouds to change spin states.

If temperature, pressure, applied electromagnetic field, or bound compound changes, a substance may exhibit one or more of these properties of magnetism listed below. If there is an electric current in the material, the changing local electric field induces a magnetic one as well. As nuanced as magnetism is, let’s get into all the types of magnetism in the world.

All Types of Magnetism #1 Diamagnetism (no collective interactions)

In diamagnetism, the paired electron orbitals are pushed into an orientation that counters an externally applied magnetic field. In a material with electron clouds full, the spin states are fixed so it has to be pulled this way. The Pauli Exclusion Principle states no two paired electrons can be in the same quantum state at once. The paired electrons orient in opposite directions, up and down, if you will. For each stably paired set of electrons, the magnetic fields thus cancel out, so the magnetic moment is zero. (The magnetic moment is the sort of “towing power” based on a flux, or gradient difference in magnetic field.)

Induce diamagnetism by applying a magnetic field to the diamagnetic material, at which point there will be a weakly repellant force from the material. The magnitude of this effect depends on the material constitution. Diamagnetism is relatively weak and only in the presence of an applied field. Field off, weakly repellant force gone.

Examples: Copper, carbon, calcite, water

#2 Paramagnetism (still no collective behavior)

In paramagnetic materials, rather than the electrons displacing in their clouds, the electrons spin around individually. Paramagnetism is also relatively weak and needs an applied field.

Electrons in paramagnetic materials are unpaired. According to Hund’s rule all the lower orbitals fill before any orbital doubles up. All the unpaired electrons can spin whichever way, they don’t have to be opposite anything because they are alone. These unpaired electrons can thus have magnetic moments in any direction. The tiny magnets line up when they’re in a magnetic field and this change creates its own change in the magnetic field. Paramagnetic materials are thus weakly attractive in an applied magnetic field.

Examples: Diatomic Oxygen (O₂), Montmorillonite clay, silicate, carbonate, aluminum

#3 Ferromagnetism – “Ordinary” Ferrous Magnetism (long range interactions)

The first permanent magnet humans worked with was lodestone, so you can remember ferrous means pertaining to iron. Ferromagnetism, unlike paramagnetism, can occur in the absence of an applied electromagnetic field.

In ferromagnetism, the magnetic dipole of the atoms line up with each other because it is energetically more favorable to reconfigure this way for stability. Once the internal structure is magnetized it retains the magnetization and slowly weaken over time. Each material has a maximal amount it can be magnetized called the saturation magnetization. The difference is that after these guys spin and orient they don’t tend to naturally go back random. You can mess with it in a magnetic field but just out there it will stay magnetized or slowly go back.

To exhibit ferromagnetism, normally the material must be below a certain temperature. Thermal motions can disturb the order so optimal magnetism is only possible at absolute zero. Also called the “permanent magnet,” Once the temperature is high enough it introduces randomness into the system and destorys the ordered domains of spin states. This temperature is called the Curie temperature (for ferromagnets).

Examples: Iron, nickel, colbalt, and many of their alloys; rare earth metals neodymium and samarium.

#4 Antiferromagnetism (non-magnetic long-range interactions)

With antiferromagnetism, the dipole moments of the atoms are in an “antiparallel” arrangement, against the magnetization field. this is the opposite direction as ferromagnets discussed above. The strength is similar to paramagnetic materials, meaning not very much. Like diamagnetic and paramagnetic materials, antiferromagnetic materials are considered non-magnetic. I know this has been of a let down so far as only one type, ferromagnetism, is actually magnetic. But don’t worry we have more to go. Antiferromagnetism is actually studied at low temperatures because it does some cool stuff there. Above what’s called the Neel temperature, thermal motions destroy the delicate antiparallel arrangment.

One notable example is antiferromagnetism is Hematite (α-Fe₂O₃) . In hematite, the crystal structure has two distinct sublattices with differing magnetic moments. When the sublattices deflect with respect to one another, a net weak magnetism occurs. It’s like two 3D grids offset and pushed and pulled apart, causing the electrons to stabalize by changing spin states and thus magnetism.

Metamagnetism

Antiferromagnets can have a variety of interesting magnetic phase transitions and phase transition features. Metamagnets refer to magnets that are either engineered or put under certain conditions to exhibit nonlinear phenomena. The seminal paper on these properties (1977) can be found here. Since then there has been research here and there, mostly in the rare ceramics used for new applications in magnetics. The studies ask “can we induce metamagnetism, in what, and under what conditions?” Also, the new landscape of a magnetic phase diagram is being catalogued, wherein many paramagnetic substances have induced magnetic “phase state,” analogous to states of matter like liquid, sold, gas where there are critical parameters in between transitions.

#5 Ferrimagnetism (long range interactions)

Magnetite (Fe₃O₄), a crystal that is also found in the brain, is the most common magnetic mineral found in earth, according to the Encyclopedia Britannica. After all, the earth magnetic field is due to the magnetism of its inner rocks. It is also ferrimagnetic, rather than ferrOmagnetic, even though it contains iron.

Ionic compounds, like table salt, have the joining of two ions, or charged elements if they were to be alone. They would be missing an electron or have an extra electron, so they bond tightly with their “partner.” Ionic ordering such in oxides (ionic compounds containing oxygen) order more complexly. The oxygen tends to space things out to give sublattices with differing magnetic moments as described in antiferromagnetic materials. The magnetic moments of the sublattices are not equal and so there is a magnetic moment ( a gradient that wants to equalize) . Magnetite has 2 lattices like this, one tetrahedral and one octahedral. This paper is a good start to learn more, but most frequently these are studied and developed for cancer treatments. Since magnetite in the brain is implicated in human memory and magnetoreception we discuss that more in depth on this site.

Side Note: Molecule based magnetism

Molecule based magnetism pervades ligands in the human body. With molecule based magnetism, a single molecule has the necessary electron cloud displacement energy to exhibit ferrimagnetism. The molecules showing this could even be sorts of organic molecules (see plastic magnets below), like carbon based ligands with a metal compound at the center. The magnetic properties often serve a role in the organism.

#6 Superparamagnetism

Superparamgenetism is an exaggerated version of paramagnetism. When a ferromagnet of ferrimagnet is small enough, the surface effects overwhelm the volume effects. The magnetic spin of the small shard acts like a single magnetic spin of an electron, effectively. Based on the surrounding environment, this tiny magnet is subject to Brownian motions, somewhat chaotic fluctuations. Every time the spin changes the magnetic field on the surface is in flux. Essentially the grains are so small they can not cooperate in aligned dipole moments. This type of magnetism is important when we talk about crystals in the body as they are often in small grains like this.

Superparamagnetism is relevant whenever we have nanoparticles so the surface interactions overwhelm that of the volume. In the body many signaling molecules and nutrients are on this order of size as well.

Single molecule based magnets

Unlike molecule based magnetism, in which a central magnetic molecule in a larger compound can exhibit magnetism, single-molecule based magnets aren’t bound to anything. These could be free in a fluid for example. These are studied and exploited because if they could retain magnetism at lab temperatures (for example 4 K) then the magnetic states can be studied for use in memory technology. To learn more here is a paper just looking at iron based single molecule magnetism.

#7 Spin glass magnetism

In a spin glass, the orientations of the electron spin are all essentially random, compared to the common ferromagnet in which they are all ordered. This disorderly spin orientation? The “glass” terminology likens the random electron spins to the positional randomness of amorphous silicon dioxide in glass. But spin glass isn’t actually glass or physically similar to glass. In spin glasses the crystalline structure is highly ordered, not amorphous like glass at all.

Spin glasses are engineered materials, studied because of the potential applications to other areas of technology. For example, control over spin states is useful in quantum computing hardware. Typically spin glasses are field cooled, meaning they must go far below the Curie temperatue, at which they tend to exhibit just paramagnetism, while a magnetic field is applied. Then the electrons set into metastable states of spin. When we remove the field the remnant magnetization is revealed – a concept for a later article (yes, crystals actually have a kind of memory of prior magnetization states). The magnetization then slowly decays with time. In purely paramagnetic materials, the magnetization falls to zero after the field is removed, with no remnant magnetization.

#8 Electromagnetism

Electromagnets exploit the fact that every changing electric field induces a magnetic field and vice verse. This is electromagnetic induction, and the basis of all motors and engines, since the magnetic force creates an actual physical push unlike the electric force which at most creates heat. (Called electromotive force)

An electromagnet is produced from a solenoid, a device in which a bar magnet like the ferromagnets discussed is wrapped with conductive wire. When a current is passed through the wire, the magnetic bar concentrates the field and its own field is enhanced. This amplifies the magnetism, often with the goal of creating a force used to push something. Speakers, MRI machines, and hard drives all use electromagnets, for example. The Lorentz force equation is usually used to calculate the theoretical force produced by charge q moving at velocity v in a magnetic field B: F=q v B sin(θ), the angle θ being that between the velocity and magnetic field.

#9 Other Types of more Rare Magnetism

Optically induced Magnetism

Here is the full fleshed out mechanisms on how simple optical interference can induce magnetization. The effect is particularly pronounced in thin dielectric films. There has been some work towards finding ideal particle combinations to control the states. Studies found spherical metamolecules in a antiferromagnetic state, typically finding toroidal resonances. In optically induced magnetism the study is toward use in optical computing systems, for the most part.

Plastic Magnets

This name is actually a bit misleading. A magnet made of organic molecules, yes, but the goal is to be more similar to biocomposites, for use in pacemakers, cochlear implants, and the like. Here is the seminal work on plastic magnets, from Ohio, funded by the US Air Force. There are also more uses now (2020 review of the technology) explored in soft robotics, and remote control of magnetic fields.

Micromagnetism

Micromagnetism is not a type of magnetism, but the study of magnetic fields in the microscopic range. This field of study includes bio-magnetics of intercellular magnetics in living things. Micromagnetism also includes materials science and engineering for devices on the microscopic range too. Mainly software is developed to take into account as many factors in the situation as possible, since at that range there is a lot going on. Then new technologies are made, mainly in medical and computing.

Gravitomagnetism

Gravitomagnetism is not magnetism at all, but just a bit technical mathematical metaphor comparing electromagnetism and gravity. However using this framework, physicists found out how to theoretically extract energy from blackholes. There is most likely other interesting implications to gravity as people play with these magnetic equations more.

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These were all types of magnetism in the world that I could find. Of course I could not explain every detail, but the concepts of remnant magnetization, surface area to volume ratio, and the crystals hematite and magnetite, are/will be discussed heavily throughout this site. The effects of magnetism in the body are not well popularized, so we cover it here.