Magnetism and Magnetised Materials

When it comes to magnetised materials, we have to talk about "magnetism" first. Experiments show that any substance can be magnetized more or less in an external magnetic field, but the degree of magnetization is different. According to the characteristics of the material in the external magnetic field, the material can be divided into five categories: paramagnetic material, diamagnetic material, ferromagnetic material, ferrimagnetic material, antiferromagnetic material.

We regard paramagnetic materials and diamagnetic materials as weak magnetic materials, and ferromagnetic materials and ferrimagnetic materials as strong magnetic materials. Generally speaking, magnetised materials generally refer to ferromagnetic substances. According to different uses, magnetised materials can be classified into several types as follows:

Soft magnetised materials: The maximum magnetization can be achieved with the smallest external magnetic field. It is a magnetic material with low coercivity and high permeability. Soft magnetic materials are easy to magnetize and also easy to demagnetize. For example: soft ferrite, amorphous nanocrystalline alloy.

Hard magnetised materials: It is also called permanent magnetic materials. It refers to materials that are difficult to be magnetized and also difficult to be demagnetized once they are magnetized, the main feature of which is high coercivity, including rare earth permanent magnetic materials, metal permanent magnetic materials and permanent magnet oxygen body.

Functional magnetised materials: It mainly includs magnetostrictive materials, magnetic recording materials, magnetoresistance materials, magnetic bubble materials, magneto-optical materials and magnetic thin film materials.