Glossary of magnets: terms from A to Z

Are you encountering terms like remanence, N52, axial, or shear force when choosing a magnet? In this glossary, we briefly explain the most important concepts in plain language. Where you can read more about them, you will find a link to a more detailed article from our knowledge center.

Go to letter: A · B · C · D · E · F · G · H · I · K · L · M · N · O · P · R · S · T · V · W · Z

A

Attraction/Repulsion

Two identical poles (north and north, or south and south) push each other away. The closer they get, the harder they push. More in Why do magnets attract or repel each other?

Alnico

Magnet material made of aluminum, nickel, and cobalt (with iron). Weaker than neodymium, but highly heat-resistant, up to about 450 to 500 °C. Often used in rod magnets for educational purposes and in measuring instruments.

Anisotropic

A magnet that has been given a preferred orientation during production. It is much stronger in that direction, but can only be magnetized in that direction. Almost all neodymium and most ferrite magnets are anisotropic. The opposite is isotropic.

Axially magnetized

The poles are located on the flat sides, for example, top and bottom of a disc magnet. This is the standard. See Axially or diametrically magnetized.

B

BHmax

The maximum energy product of a magnet material, expressed in MGOe. The number in the grade designation (such as N42) is the BHmax: the higher, the stronger the material. See What does BHmax mean?

Block magnet

Rectangular magnet, indicated as length x width x height. Usually magnetized through the thickness. See Which block magnet do you choose?

Br (remanence)

The magnetic flux density that a material retains after it has been magnetized, in tesla. For neodymium, this is around 1.2 to 1.45 T. See What is remanence (Br)?

C

Coating

Protective layer on a magnet, as neodymium rusts easily. The best-known is NiCuNi (nickel-copper-nickel); in addition, there are epoxy, plastic, and rubber. See Which coating do you choose?

Coercivity (Hc)

How well a magnet resists demagnetization, for example, due to an opposing magnetic field or heat. See What is coercivity (Hc)?

Curie point

The temperature above which a material completely loses its magnetism. For neodymium, this is around 310 to 400 °C, but the strength already decreases permanently starting from the maximum operating temperature. See What is the Curie point?

D

Demagnetizing

The (partial) loss of magnetism due to heat, a strong opposing field, or hard impacts. See Why do magnets lose their power?

Diametrically magnetized

The poles are located on the rounded sides instead of the flat sides. Used in sensors, motors, and rotating applications. See Axially or diametrically magnetized.

Threaded bush

A bush with an internal thread (e.g., M4 or M6) on top of a pot magnet, into which you screw a bolt, hook, or eyelet. See pot magnets with threaded bush.

Threaded stud

A protruding threaded stud on a pot magnet, which you pass through a hole and secure with a nut. See pot magnets with threaded stud.

E

Epoxy

Plastic coating that is more resistant to moisture than nickel. Recognizable by its black or gray color. If damaged, the magnet can still rust. See epoxy magnets.

F

Ferrite

Ceramic magnet material made of iron oxide. Weaker and cheaper than neodymium, but does not rust and can be used up to approximately 200 °C. See Neodymium, ferrite, or samarium-cobalt.

Ferromagnetic

A material that is strongly attracted by a magnet, such as iron, steel, nickel, and cobalt. See Which metals are magnetic?

Flexible magnet

Pliable magnet in which magnetic powder is incorporated into rubber or plastic, such as our magnetic strips. Weaker than solid neodymium magnets, but can be cut to size.

Flux density

The strength of the magnetic field at a specific location, expressed in tesla or gauss.

G

Gauss

Unit of magnetic flux density. 10,000 gauss equals 1 tesla. See What is Gauss and Tesla?

Sintered

Production method in which magnetic powder is pressed and heated into a solid block. This is how most neodymium magnets are made. See How are neodymium magnets made?

H

Hook magnet

Pot magnet with a hook in the threaded bush, for hanging items. See hook magnets and Hook magnet or eyelet magnet?

Holding force

The force required to pull a magnet perpendicularly away from a thick, flat steel plate, expressed in kg. A laboratory value: in practice, the force is lower. See How is the holding force determined?

I

Isotropic

A magnet without a preferred orientation, which can be magnetized in any direction, but is weaker than an anisotropic magnet.

K

Ball magnet

Spherical magnet, popular for crafts and demonstrations. See Which ball magnet do you choose?

Cube magnet

Block magnet with equal sides. See Which cube magnet do you choose?

L

Air gap

Any distance between magnet and steel: paint, foil, tape, fabric, or a gap. With small magnets, half a millimeter can reduce the holding force by a quarter to more than a third. See Can magnets work through wood, glass, and plastic?

M

Magnetic field

The area around a magnet in which it exerts force. See What is a magnetic field?

Magnetization direction

The direction from north to south pole in the magnet: axial, diametrical, or in strips (multipole).

Maximum operating temperature

The highest temperature at which a magnet retains its force. Standard neodymium (without a letter after the number) up to 80 °C. See Magnets at high temperatures.

Multipole

A magnet with multiple north and south poles side by side, such as with magnetic strips. This allows it to hold well flat against steel, but the field depth is shallower.

N

N-grade (N35 to N52)

The quality of neodymium: the higher the number, the stronger the material for the same size. An N52 holds about a quarter more than an N42 of the same size. See What does N35, N42, N48, and N52 mean?

Neodymium (NdFeB)

Magnet material made of neodymium, iron, and boron: the strongest permanent magnets available. See What is neodymium?

NiCuNi

Standard coating of nickel-copper-nickel. Shiny silver, wear-resistant, but not suitable for long-term use in moisture. See Why do neodymium magnets have a coating?

North pole and south pole

The two ends of a magnet. Opposite poles attract each other, identical poles repel each other. See Why do magnets attract each other?

O

Eyelet magnet

Pot magnet with an eyelet in the threaded bush, for a rope, carabiner, or chain. See Which eyelet magnet do you choose?

P

Permanent magnet

A magnet that retains its magnetism on its own, without electricity. The opposite of an electromagnet. See How does a magnet work?

Permeability

How well a material conducts a magnetic field. Steel conducts well, air, wood, and plastic almost not at all.

Pot magnet

Magnet in a steel pot, which concentrates the force on one side. Consequently, it is much stronger than a loose magnet of the same size. See pot magnets and Why are pot magnets so strong?

R

Ring magnet

Round magnet with a hole in the middle, often with a countersunk hole for a screw. See Which ring magnet do you choose?

Rubber-coated

Magnet or pot magnet with a rubber layer. Protects paint and provides grip, preventing it from sliding easily, but the holding force is lower. See rubber coated magnets.

Stainless steel (RVS)

Most types (such as 304 and 316) are not or hardly magnetic. See Is stainless steel magnetic?

S

Samarium-cobalt (SmCo)

Strong magnet material that can be used up to about 250 to 350 °C and is highly resistant to corrosion. More expensive than neodymium. See Neodymium, ferrite, or samarium-cobalt.

Disc magnet

Round, flat magnet, indicated as diameter x height. The most commonly used shape. See Which disc magnet do you choose?

Shear force

The force at which a magnet begins to slide along a surface, for example, on a vertical wall. With steel on steel, approximately 15 to 25% of the holding force. See Holding force, pulling force, and working load.

Rod magnet

Elongated round magnet, magnetized along its length. See Which rod magnet do you choose?

Steel tape

Self-adhesive strip of steel, not magnetic itself, which serves as a base on which magnets attach. Not to be confused with magnetic tape.

T

Temperature class (M, H, SH, UH, EH)

Letters after the N-grade indicating the maximum temperature at which neodymium is usable: without a letter up to 80 °C, M up to 100 °C, H up to 120 °C, SH up to 150 °C, UH up to 180 °C, and EH up to 200 °C. See Magnets at high temperatures.

Tesla

SI unit of magnetic flux density. 1 tesla is 10,000 gauss. See What is Gauss and Tesla?

Pulling force

The force with which a magnet pulls on something. Often used interchangeably with holding force. See Holding force, pulling force, and working load.

V

Countersunk hole

A sloped hole in a magnet, through which the head of a countersunk screw sits flush. See pot magnets with countersunk hole.

Fishing magnet

Strong pot magnet with an eyelet, to retrieve metal objects from water. See Which fishing magnet do you choose?

W

Working load

The weight that you can safely hang from a magnet in practice. Always much lower than the holding force. See Holding force, pulling force, and working load.

Z

Rare earth metals

Group of seventeen elements, including neodymium and samarium. See What are rare earth metals?

Self-adhesive

Magnet with an adhesive layer on one side, so you can mount it without drilling or screwing. See self-adhesive magnets.

Are you missing a term, or are you unsure which magnet suits your application? Use the Magnet Advisor or contact us.