• Question: how are magnets created?

    Asked by anon-321435 on 1 Apr 2022.
    • Photo: Jamie Smith

      Jamie Smith answered on 17 Mar 2022:

      Hi, thanks for your question!

      The easiest magnet to make is an electromagnet. Any electrical current flow creates a magnetic field around it. By coiling a cable, the magnetic field created by each ring is in the same direction and combines to create a stronger one. This is called a solenoid, and has similar properties to a bar magnet (North at one end, South at the other). You can also control the strength of this magnet by how much current you put through it which makes it quite useful for certain applications. In fusion, we can turn different “poloidal coils” on and off to control the position of the plasma fuel within the fusion reactor.

      I don’t know as much about making permanent magnets, but generally you need to align the atoms in certain materials (like iron) in one direction. This can be done by repeated exposure to another magnetic field in the same direction, but there are probably better industrial methods that I’m not sure of myself.

    • Photo: Luke Humphrey

      Luke Humphrey answered on 17 Mar 2022:

      Hi again Miss Goodin, another great question.

      The short answer is:
      1. Create an electromagnet using electricity.
      2. Create a permanent magnet by exposing certain materials to a magnetic field.
      3. Use a material which is naturally magnetic, these materials are found underground in mines and sometimes mixed together to make stronger magnets.

      The long answer is:
      Magnetism is a really weird concept that requires an understanding of special relativity and quantum physics to truly understand. About 120 years ago, scientists discovered that electricity and magnetism were “two sides of the same coin”. They combined both phenomena into a single theory (“theory” in science doesn’t mean “guess”, it means “a way of explaining something”). This new theory was called electromagnetism, and it led to Einstein’s famous theory of special relativity.

      Einstein’s theory showed that objects that move very fast actually get squashed in the direction they’re moving. However, there’s a really weird catch: the objects only get squashed from the perspective of things that are staying still. If you were moving at the same speed, they would look normal and everything else would look stretched!

      The squashing and stretching doesn’t usually doesn’t matter much, as it’s only by a very tiny amount unless you’re moving close to the speed of light (about a million times faster than a train!)
      However, for very small things like electrons flowing in a wire, even being squashed a little bit makes a big difference! When the electrons squash together, their electric force becomes stronger, which means they can attract or repel charged objects.

      Don’t worry if this seems complicated, this is a topic that is taught at university level! The point is that a magnet is really created by the movement of electrons in the material.

      The simplest type to understand are electromagnets, where the magnetic field is produced by the flow of electrons in a wire. Jamie has already explained this. There are also three main kinds of magnetism in materials: Diamagnetism, Paramagnetism, and Ferromagnetism.

      These types of magnets are mined from the ground and include some common metals like iron, as well as some very rare metals called “rare earth” elements. Rare earth alloys like neodynium are some of the strongest permenant magnets around. Some materials only become magnetic when you expose them to other magnets, which “turns on” their magnetic properties.

      I hope this helps!

    • Photo: Jan Sprengel

      Jan Sprengel answered on 18 Mar 2022:

      Hi, believe it or not, I’m not an expert on how permanent magnets are created, which is kind of terrible of me given I work with magnetic fields a lot…

      The best explanation I can give is that when we imagine materials, we must think of them as bunch of very tiny molecules (atoms). There’s SO many of these atoms – one grain of sand has 10^19 atoms in it! That’s a number with 1 at the beginning and 19 zeroes behind it! Think about the largest number you can imagine, double it and it still will probably be smaller than the number of atoms in a grain of sand!
      Each of these atoms is actually a very tiny magnet itself! The reason that all things around are not magnetic is because these atoms are in constant motion, rotating all around, which causes these tiny magnets to position in all sorts of different directions. If you have identical two bar magnets, you can place them next to each other, one pointing north pole and the other south pole in the same direction. Then you can try position 3rd identical bar magnet next the opposing poles, the 3rd magnet will stay in place, because one magnet tries to push it away, and the one tries to attract it 😀 – what happened is that magnetic fields of the first two magnets are CANCELLED by each other. That’s basically what happens in any material – moving atoms position in all sorts of directions and cancel each others magnetic field, so the whole body is not magnetic.
      But if you ever played with magnets, you probably know that metal (specifically iron/steel) items are attracted by magnets. If you again use your two bar magnets, position them apart, and you try moving one of the closer to the other one, you will see that the magnet will rotate on your desk and attract so that south pole of one magnet touches the north pole of the other. If we go back to our atoms (which are tiny magnets), similar thing happens. If we move magnet closer to an iron item – atoms rotate so their south poles point towards north pole of our permanent magnet and suddenly our item becomes a magnet itself 😀 but when you pull the permanent magnet away the atoms start to rotate again and iron stops being a magnet 🙁 so we cannot easily create a permanent magnet ourselves)
      The scientists (not me) found a workaround to this problem. We basically take a special iron in which our atoms are super tightly packed so they cannot move or even rotate much (think about overcrowded bus!). Then we put a SUPER STRONG MAGNET next to it – as we talked the atoms will try to rotate and point their magnetic poles towards the magnet, but they will do it very, very slowly. If we wait enough, the atoms in time will position and all point towards the magnet and get attracted. Then we.. take the magnet away. And here’s the trick – the atoms are SO PACKED that they cannot easily rotate back and so they stay in their position, all point their north pole in one direction and south pole in opposite, which exactly what happens in other magnets! And voila, we tricked the atoms to create a magnet! 😉
      The atoms will still try to rotate, even when super packed, but it takes them a lot of time – that’s why after a few years your fridge magnets start dropping from the fridge 😀

    • Photo: Daisy Shearer

      Daisy Shearer answered on 20 Mar 2022:

      Magnetism is fascinating.

      I work with a huge superconducting electromagnet that needs to be cryogenically cooled to produce big magnetic fields so that’s one type of magnet and probably the one that is used the most in technology. Basically, when you put an electric current through a wire, it generates a magnetic field around it! We find that if we get some metal wire and curl it around into a spiral shape, it produces a magnetic field much like a bar magnet (the type you might have used in science classes). In my case, we use a superconducting material to make the wires which means that the electrical current going through the wires is HUGE and a huge magnetic field can be produced– stronger than around 700 fridge magnets.

      Of course, this isn’t the only way to make a magnet. Some materials are inherently magnetic and we call these permanent magnets. You can also make temporary magnets by bringing certain materials close to a magnet. This causes the magnetic domains inside the material to align and it becomes a magnet too, but this only lasts while the magnet is close to the material.

      To make things even more complicated, there are lots of different types of magnetism, such as diamagnetism, paramagnetism, and ferromagnetism. There’s also a type of material called ‘spin glass’ which is magnetic and is related to the research I do! The world of magnetism is vast and really interesting once you delve into it 🧲