Magnetic Properties of Materials and Types of Magnetic Material

In This Post, we are going to discuss Magnetic Properties of Materials and Types of Magnetic Material, this topic will help you to understand magnetic materials. 

Magnetic Properties of Materials

• Magnetic materials are those materials within which a state of magnetization may be evoked.
• The magnetic susceptibility depends on the nature of the magnetic material and its state, that is, temperature, etc.
• The principal ferromagnetic elements are iron, cobalt, nickel.
• The Curie-Weiss law states that

where x = susceptibility, C = Curie temperature and Thita = paramagnetic Curie temperature.

• When a ferromagnetic material is magnetized small changes in dimensions occur, the effect is known as "magnetostriction".
• Diamagnetism is the property of material due to which it when placed in a magnetic field, becomes weakly magnetized in a direction opposite to the magnetization of the external fields. Practically all organic substances are diamagnetic.
• The magnetic properties of all ferromagnetic materials depend upon their chemical composition, mechanical working and heat treatment. The general effect of impurities is to decrease the permeability and increase the hysteresis loss.
• Permanent-magnet materials may be grouped into five classes as follows :

(i) Precipitation-hardened alloys

(ii) Quench-hardened alloys

(iii) Ceramic

(iv) Iron powder compacts

(v) Work-hardened materials.

• Iron losses if allowed to take place unchecked, not only reduce the efficiency of electrical equipment but also raise the temperature of the core. Hence these losses should be kept as small as is economically possible.
• Total iron loss is given by the relation

where Pi = total iron loss, Ph = hysteresis loss, Pe = eddy current loss, Kh = hysteresis co-efficient, F = frequency, B(max) = maximum flux density, k = Steinmetz co-efficient and Ke = constant-eddy currents.

• Magnetic hysteresis is defined as the lagging of magnetization or induction flux density (B) behind the magnetizing force (H) or it is that quality of a magnetic substance due to which energy is dissipated in it on the reversal of its magnetism.
• Ageing of a permanent magnet is the process of normal or accelerated change, under continued normal or specified artificial conditions, in the strength of the magnetic field maintained. Metallurgical ageing is the result of a change in the metallurgical condition of the magnet, which changes its ability to remain in a magnetized condition.

Types of Magnetic Materials

1 - Diamagnetic materials

Diamagnetic materials are those that generally consider non-magnetic and include water, wood, most organic compounds such as petroleum and some plastics, and many metals, including copper, particularly heavy ones with many central electrons, such as mercury. , gold. and bismuth.

Source - Diamagnetic materials

2 - Paramagnetic Materials

Materials that are called "Paramagnetic Materials" are those that exhibit, at least in an appreciable temperature range, magnetic susceptibilities that adhere to the Curie or Curie-Weiss laws. In principle, any system that contains atoms, ions or molecules with unpaired spins can be called a Paramagnetic Material, but the interactions between them must be carefully considered.

Source - Paramagnetic Materials

3 - Ferromagnetic Material

Ferromagnetic materials are those substances that exhibit a strong magnetism in the same direction of the field when a magnetic field is applied.


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