There are several materials that magnets are made of including NdFeB (Neodymium-iron-boron), AlNiCo and ferrite. The properties of these materials vary in terms of cost, strength per unit volume, behavior over temperature, and manufacturing tolerance.
Magnets can be formed into many shapes which are advantageous for different applications. For example, ring magnets are commonly used to sense speed and direction. Arnold Magnetics has a good description of how to choose a magnet for a given application: Permanent Magnet Applications Guide
A list of magnet vendors recommended by our customers follows.
Allegro Hall Effect devices provide maximum and minimum magnetic switching thresholds which are guaranteed over supply and temperature and most are designed to work with magnets with a low temperature coefficient like Samarium Cobalt or Aluminum Nickel Cobalt.
The following 2-wire switches are designed for improved performance with ferrous magnets, with a typical -0.25%/K change in magnetic switchpoints over temperature: A115x_F and A119x_F.
Concentrators, which can be called called controllers, cores or shields, depending on the application, are used to increase the sensitivity of a given solution. This can also allow an increase in air gap, the use of a smaller magnet, or deployment of a lower sensitivity Hall effect sensor. See these resources for more information:
Customers have recommended concentrators from:
Magnetic Shields may be required in some applications to block the magnetic field. Here is a list of magnetic shield vendors Allegro is aware of:
This information is provided solely for information and convenience. It is not intended to be an exhaustive list of resources for magnets. The inclusion of any company listed herein does not expressly or impliedly indicate any affiliation with or endorsement of that company. Allegro therefore makes no warranties or representations, express or implied, about: such companies, the information or products such companies may provide, or the suitability or quality of any of their products or services. Allegro has no obligation to keep this list updated. Any supplier not currently included in this list, but that desires to be included, may contact Allegro’s webmaster
Post date: June 23rd, 2016