Question

The susceptibility of a magnetic material is $- 2.6 \times 1{0^{ - 5}}$ . Identify the type of magnetic material and state its two properties.

Answer 1

Magnetic susceptibility is a dimensionless proportionality constant which indicates the degree of magnetization of a magnetic material in response to applied magnetic field. It is caused by interactions of electrons and nucleus with the externally applied magnetic field. The magnetic susceptibility is calculated using the formula: $\chi = \dfrac{M}{H}$ where $\chi$ is the magnetic susceptibility, $M$ is the magnetization and $H$ is the field intensity.

Complete step by step solution:
In simple words, magnetic susceptibility can be defined as the measure of how much a material will be magnetized in an applied magnetic field. Based on the value of $\chi$ we have three types of magnetic materials:
Paramagnetic materials: The materials which align with the magnetic field are known as paramagnetic materials. For these materials the magnetic susceptibility is $\chi > 0$ which means it is always a small positive value for paramagnetic materials. Examples of paramagnetic materials are: Aluminum and oxygen.
Diamagnetic material: Diamagnetic materials are magnetic materials which can align against the magnetic field. Magnetic susceptibility for such materials is $\chi < 0$ which means it is always a negative value for diamagnetic material. Diamagnetic materials are repelled by the magnets and they move from a stronger field to a weaker field. Diamagnetic materials are not temperature dependent. They do have a small amount of magnetization intensity. Example: Gold, tin, mercury and mercury.
Ferromagnetic material: Ferromagnetic materials are materials that are highly magnetized in a magnetic field. These are highly attracted by the magnets. Magnetic susceptibility is very high and positive. Examples: Iron, cobalt, nickel and their alloys.

Since the magnetic susceptibility of the given material in the question is negative therefore the material is diamagnetic.

Note: There are many other examples for the above three types of magnetic material. Ferromagnetic materials do not have a constant relative permeability and vary from $1000$ up to $100000$. Paramagnetic materials depend on temperature and are weakly attracted by magnets with relative permeability $1.00001$ to $1.003$.