Halbach Array Magnet

The major advantages of Halbach Arrays are that they can produce strong magnetic fields on one side whilst creating a very small stray field on the opposite side. This effect is best understood by observing the magnetic flux distribution.

It is an ideal structure in engineering. It uses the arrangement of special magnet units to enhance the field strength in the unit direction. The goal is to produce the strongest magnetic field with the least amount of magnets.

Product application

Halbach arrays are widely used today and are used in systems of varying complexity. Perhaps the most common example of a Halbach array is a flexible fridge magnet. These thin, flexible magnets are often printed as fridge magnets or stuck on the back of cars. They are much weaker than neodymium magnets (only 2-3% of them), but are inexpensive and very useful in this type of application. In this case, the one-sided flux property is used to enhance the magnet's holding power. It is also possible to combine different arrays of bar magnets to create a simple locking system.

A more advanced example of a Halbach Array in action is in a Maglev train track or Inductrack, where magnetic levitation is used to support the carriage. The magnetic arrays lift the train a small distance above the track and can support a weight of up to 50 times that of the magnet. The operation is based on the principle of induction; as the array is passed over the metallic track coils, the variations in the magnetic field induce a voltage in the track. The track then creates its own magnetic field and, similarly to when you attempt to push the two like poles of neodymium bar magnets together, when this field aligns with the field produced by the Halbach Array, repulsion causes the train to levitate.

Halbach arrays are also used in advanced scientific experiments such as synchrotrons and free-electron lasers, where they are known as Halbach ‘wigglers’. FELs have a very wide and highly tunable frequency range and are used in many applications, ranging from medical to military.

Case

The main disadvantage of the Halbach array geometry is the difficulty in assembly. All the magnetic elements in the Halbach array repel each other, which can lead to various assembly problems, such as the need to fight the 'magnetic force' during the assembly process to ensure the integrity of each magnet. Another disadvantage is that the magnets are arranged in a direct or quasi-direct repulsion. This means that magnets in the same array will demagnetize their neighboring magnets. For high coercivity alloys, this may not be a problem unless high temperatures are required in the application - as the operating temperature increases, the magnets are more likely to demagnetize, and the demagnetization of adjacent magnets will also increase.

Dexinmag team is committed to providing customers with high-quality Halbach arrays with high coercivity and magnetic distribution. We have a professional simulation data platform, simulation software and superb/safe assembly process. The following are some cases provided by Dexing team to our professional customers，（Most of them have an 'air gap' in the middle, this is because the air gap can significantly improve the efficiency of the Halbach magnetic circuit.）

0.7T Halbach ion source
Halbach thruster
Electron beam Halbach
96-pole small Halbach array
Face 4-pole Halbach array
High linear Halbach array
27mm small Halbach rotor

Halbach Arrays or magnet geometries utilizing a ''Bucking-Magnet'' can improve the efficiency of the magnetic circuit.

Halbach Arrays can be circular or Planar, and they have one predominant side/surface where a majority of the magnetic field resides.

Halbach Arrays may have an issue in high heat applications, because the array elements apply a demagnetizing field on each other.

Halbach Arrays work better than conventional arrays when a ''gap'' is present in the application.

There are many opportunities for a Halbach design to improve performance. Consult Dexinmag Company for application assistance with your array design to see if a Halbach Array can enhance your magnetic applications

When we get in touch, please let us know your:

• Application
• Magnetic field requirements
• Polarity distribution
• Dimensions (if restrictions)