Is your magnet isotropic or anisotropic?

Is your magnet isotropic or anisotropic? And what does it mean?

We are in some of the more peripheral physics where only the die-hard magnet fans hang on. Welcome to the club of magnet supporters.

But back to isotropy and anisotropy: it is about whether a magnet has a certain direction or not.

What is isotropic material?

The magnetic poles land bump to bump when casting a magnet. If 70% of the magnetic material has the north pole out and 30% is with the south pole out, then it will be a north pole but only at 70% of full strength. This is what we refer to as isotropic.

Isotropy is the easiest solution, but it's also the weakest.

What is anisotropic material?

You can choose to post-treat the magnet to make it anisotropic. In practical terms, the magnet is exposed to a strong magnetic field that turns all the magnetic material so that all the poles face the same direction. This means that you now have 100% north poles one way and 100% south poles the other way, the magnet achieves full strength thanks to this.

This is a little more expensive because it takes a bit more work and equipment, in return, you get a stronger magnet.

A little rule to remember

When working with physics, rules to remember are nice to work with. So here comes a small (slightly clumsy) rule of thumb for the difference between isotropic and anisotropic materials: the shortest word isotropic is also the material with the shortest production time. When you add an 'an' and make the word longer to anisotropic, it also represents a longer production time. So it starts as isotropic material and then you process it into anisotropic material.

Why is anisotropic material not always rejected?

The anisotropic finishing is widely used for magnetic tape, but why don't two pieces of magnetic tape repel each other? Magnetic tape has magnetic stripes on it, which is why they don't. If you don't have a magnetic tape to test with at the same time, it's hard to explain because you can clearly feel it when you try to put two pieces of magnetic tape against each other. But we still try to describe it in words, even though we take it as a challenge.

Imagine a football pitch where you walk with the lawnmower and switch direction when you get to the end: then you will see the classic stripes on the football field because the grass faces different directions and thus has a slight color difference. It is somewhat the same with the magnetic tape: you swipe the poles in one row at a time, so that you obtain partially mixed poles - i.e. a row with north and a row with the south poles outwards... and then north again, etc. all the way down the magnetic foil.

This is also why you must make sure to put 2 pieces of magnetic tape against each other before you cut if you need to use it as magnets opposite each other. The magnetic tape must capture the right pole path so that it is attracted (it feels like as a small push or jerk in the magnetic tape when you do not catch the poles correctly... but the poles are strong and are therefore "automatically" attracted in the direction of the strongest field). And if you have cut it in advance, a slight skew can occur.

Iso standard = ninja

We continue to want to learn more about magnetism even though there is no definite magnet education. Our goal is to make magnetism more understandable, because magnets are so brilliant for so many things. The more we know, the better we can advise you in choosing magnets for your project, so that it is correct and perfect from the start.
It's very popular to throw out a bunch off your ISO certifications as a business. Since there is no certification within magnet geekery, we pride ourselves on being Iso Ninja certified according to Danish standards... as the only ones in Denmark. And you are very welcome to test our knowledge, because we follow the same philosophy as Pippi:

If we don't know something, we can help you figure it out!

If reading our FAQ is not sufficient, the we would love to hear from you so we can make it even better.