What Determines the Strength of a Magnet?
There are many different kinds of magnets. They come in different sizes, shapes, materials and strengths. They all generate a force called magnetism. This force is what allows them to attract or stick to certain metals. Yet some magnets can’t even hold a piece of paper to a refrigerator, while others can lift cars high up into the air. So, what is it that determines the strength of a magnet?
Type of Material
Every substance is made up of tiny units called atoms. Every atom has electrons. Electrons are constantly in motion. Their movement generates an electric current, which causes each electron to act like a tiny little magnet. Most substances have an equal number of electrons spinning in opposite directions, which cancels out their magnetism. But some substances are strongly magnetic, which means most of their electrons spin in the same direction. These substances have high magnetic permeability and make the strongest magnets. Iron, cobalt and nickel are among these substances. Neodymium iron boron (NdFeb) makes the most powerful magnets. Neodymium magnets are so powerful, in fact, that a NEO magnet weighing only a few grams can still attract up to 1,000 times its own weight.
External Magnetic Field
To turn a substance into a magnet, it must be exposed to the magnetic field of an existing magnet. The more powerful the external magnetic field applied, the stronger the resulting magnet will be.
What about Size?
Does bigger mean stronger? When you magnetize a piece of iron, the north-seeking poles of the atoms align. The force generated by the aligned atoms creates a magnetic field. A larger piece of iron would have more atoms to align, potentially resulting in a stronger magnetic field than a smaller piece of the same material. However, in the case of an extremely long piece of iron, there is an increased risk that stray magnetic fields will misalign atoms and actually decrease the strength of the magnet’s magnetic field.
Selecting the Right Magnet
Although not a big factor in determining the strength of a magnet, size and shape can matter just as much depending on the application. We offer a full selection of industrial and promotional magnets in a variety of sizes, shapes and strengths, and would be happy to help you find the right magnet for your project. Shop our online magnet store, give us a call at 763-540-9497 or send us a message.