Halbach array is a special arrangement of permanent magnets which enhances the magnetic field on one side while weakening on the other side. The principle was first invented by James (Jim) M. Winey at Magnepan in 1970.
However, it was Klaus Halbach (a German) who designed the Halbach array while he was at Berkeley Lab. Although Mr Halbach is very successful as a particle accelerator designer, he is best known for his work on magnetic systems for particle accelerators. During the 1980s, he invented the halbach array which was used to focus electron beams of accelerators.
Nowadays, Halbach array has become a common design in the magnet industry and is used in various applications. For example, there are halbach electric motor and halbach magnetic coupling.
According to shape, halbach array magnets can be divided into three types: linear, circular and arc halbach.
One of the applications for linear halbach is a flexible refrigerator magnet. A refrigerator magnet has strong magnetic field on its working face, while the magnetic field on the other side is close-to-zero.
Many electronic devices also employ the advantage of linear halbach array. Take an iPad for example, they use linear halbach design so that Apple pencil can snap precisely to the point where the charging coils are aligned. (Read more)
Basically, there are three types of configuration for a halbach ring or cylinder: 1) dipole 2) quadrupole and 3) sextupole. For a dipole (N=1), the arrow of magnetization rotates 60° from one magnet to another. For a quadrupole type, the arrow rotates 90° and sextupole 120°.
In the real application, the magnets are combined with adhesive and mostly fixed and protected by a metal sleeve on the outside. Arc halbach is considered when a single circular assembly is difficult to make. It is a sub-assemblies for circular halbach.
Oftentimes, customers demand more complex design of circular halbach array. Therefore, nearly all halbach arrays are custom-made according to customer’s drawing. At Tengye, we have used different permanent magnet materials such as NdFeB and SmCo. We’ve been expert at manufacturing halbach arrays for two decades. We know how to assemble magnets in a precise and efficient way.
About Tengye: Tengye supplies finest permanent magnetic materials and assemblies to world industry. We work closely with our customer from designing stage to mass production.