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Neodymium magnets are made with a preferred magnetization direction which can not be changed. These materials are either manufactured in the influence of strong magnetic fields or pressed a specific way, and can only be magnetized through the preferred axis.Sintered Neodymium (Iron Boron) and Samarium Cobalt magnets are anisotropic.

In the picture at right, it is the area inside the box, under the curve.

Some folks (like physicists) use a magnetic dipole model to simulate or mathematically model a magnet or group of magnets. Mathematically, it's easier than considering the complexities of weird magnet shapes. It's not theoretically perfect. Using it won't always match measured field strengths near a neodymium magnet. It works great for a sphere, but isn't correct near other shapes like discs or blocks. It's a great approximation when you're measuring far away from a magnet, but not so good close up, especially near the edges of a magnet.

Calculate the dipole moment using the formula

**Br**is Br max, the Residual Flux Density, expressed in Tesla.**V**is the volume of the magnet, expressed in cubic meters.**μ**is the permeability of a vacuum, or 4 π x 10_{o}^{-7}N/A^{2}.

With soft materials, which are generally used in alternating circuits, the area inside this "loop" should be as thin as possible (it is a measure of energy loss). But with hard materials the "fatter" the loop, the stronger the magnet will be.

The first quadrant of the loop (that is +X and +Y) is called the magnetization curve. It is of interest because it shows how much magnetizing force must be applied to saturate a magnet. The second quadrant (-X and +Y) is called the Demagnetization Curve.

A graphic explanation can be found here.

If you take a bar magnet and break it into two pieces, each piece will again have a North pole and a South pole. If you take one of those pieces and break it into two, each of the smaller pieces will have a North pole and a South pole. No matter how small the pieces of the magnet become, each piece will have a North pole and a South pole. It has not been shown to be possible to end up with a single North pole or a single South pole which is a monopole ("mono" means one or single, thus one pole).

Our online Pull Force Calculator can calculate Pc for common shapes. It assumes a single magnet in free space. Other nearby magnets or ferromagnetic materials can change matters.

The magnetic permeability of a vacuum (µ

We test for two different values of pull force using two different setups. Read more about these two pull forces here.

February

Specials

10% Off

SB443-IN

Stepped Block Magnets

1/4" x 1/4" square

10% Off

MM-A-42

Mounting Magnets

42mm diameter

Order by phone:

1-888-SHOP-KJM

(1-888-746-7556)

or 215-766-8055

Order online for

fastest shipping!

K&J Magnetics, Inc.

Your online source for incredibly powerful neodymium magnets

Specials

10% Off

SB443-IN

Stepped Block Magnets

1/4" x 1/4" square

10% Off

MM-A-42

Mounting Magnets

42mm diameter

Order by phone:

1-888-SHOP-KJM

(1-888-746-7556)

or 215-766-8055

Order online for

fastest shipping!

No Minimum Order!

K&J Magnetics, Inc.

Your online source for incredibly powerful neodymium magnets