The Halbach Array Experiment: Redefining the Science of Magnetic Adhesion

Want to increase the magnetism of your magnets? - Use a magnet array

I need a small but super-strong magnet.

We have a magnetic knife rack, typically using a few small neodymium magnets to enhance magnetism. However, when adding more knives, conventional magnets may not provide enough strength to support their weight. This guide comes to the rescue, demonstrating a small experiment to create a reinforced powerful magnet.

I took 5 cubes (2mm x 2mm x 2mm) of neodymium magnets and arranged them in various configurations to visually experience the magnetic force of the Halbach array.

1. There are many ways to achieve this, but I will discuss four:Aligning the poles - Stacking the magnets side by side with all the north poles pointing in the same direction.
2. Creating a Halbach array - Halbach array is a specific magnet arrangement that results in one side of the array having a very strong magnetic field, while the other side has a much weaker field, arranged as north right, north up, north left, north down, north right.
3. Creating an inverse Halbach array - Similar to method three but with opposite pole directions, arranged as north left, north up, north right, north down, north left.
4. Alternating poles - Stacking the magnets side by side with alternating pole directions; north up, north down, north up, and so on.

In method one, all the north poles are aligned to the left. (Note: The arrows in the diagram point to the north pole of the magnets.)

Method two displays the specific arrangement of magnetic poles known as the Halbach array. The Halbach array provides a significantly stronger magnetic field on one side and a much weaker field on the other, arranged as north right, north up, north left, north down, north right.

In method three, two different arrangements of the Halbach array are compared to test if their performances differ. The magnets are arranged in a pattern with alternating north pole directions; north left, north up, north right, north down, north left.

In method four, the magnets are arranged in a pattern with alternating north pole directions; north up, north down, north up, and so on.

I found a couple of websites that describe the Halbach array, such as Wikipedia and TOPMAG (TOPMAG is the source of the charts. They are an excellent resource for any magnet you can imagine!).

PS If you find the guide I've posted interesting, please click the 'Follow' button above. Thank you!

Experimental Equipment:

Regular cup

rope

transparent plastic bag

small magnetic needle

rectangular box

glue gun

steel balls

5 square magnets

1.First, use a small magnetic needle to determine the magnetic direction of the magnets and mark each small piece accordingly.

2.Use a glue gun to attach a short length of rope to the rectangular box, serving as a hook to connect with a plastic bag, creating a small and simple packaging box.

Following method one, place the arranged magnetic strips into the box and use the magnetism of the magnets to secure the device onto the iron plate

Slowly place steel balls into the plastic bag and observe that the arrangement in method one can accommodate up to 14 steel balls at most

Adopting the arrangement from Method Two, it was discovered that the number of steel balls that can be accommodated significantly increased, with a maximum capacity of up to 112!

Using the arrangement from Method Three, only 9 steel balls can be accommodated

Using the arrangement from Method Four, it is possible to accommodate 41 steel balls.

In this experiment, we arranged magnets in different sequences, both vertically and horizontally, allowing for the suspension of varying numbers of steel balls below. This demonstrates that the magnetic field strength above each small magnet is different. Some specific arrangements enhance the magnetic field strength in a particular direction of the small magnet. This unique structure is known as a Halbach array, where the magnetization directions of individual magnets rotate at specific angles in the array, producing the strongest magnetic field with the minimum number of magnets. Magnetic field lines concentrate above the small magnets, reaching their maximum strength, while below, the magnetic field lines are sparse, forming an approximate sinusoidal distribution in space