# What is Langevin theory of paramagnetism?

## What is Langevin theory of paramagnetism?

Langevin’s classical theory of Paramagnetism: Langevin considered a paramagnetic gas containing N atoms per unit volume each having a permanent magnetic moment μ. In the presence of a magnetic field H, these dipoles tend to orient themselves in the direction of the field in order to minimize their energy.

What are the drawbacks of classical theory of paramagnetism?

The susceptibilities of a paramagnetic material is inversely proportional to the temperature. But, experimental result shows that para-magnetism of a metal is independent of temperature. Moreover, the ferro-magnetism cannot be explained by this theory.

What is the theory of ferromagnetism?

Ferromagnetism is a magnetically ordered state of matter in which atomic magnetic moments are parallel to each other, so that the matter has a spontaneous magnetization. Owing to ferromagnetism, some materials (such as iron) can be attracted by magnets or become the permanent magnets themselves.

### What is the formula of paramagnetism?

Paramagnetism. mu = g { S ( S + 1 ) }1/2 where mu = effective magnetic moment g = 2.0023 S = 1/2 for one unpaired electron 1 for two unpaired electrons 3/2 for three unpaired electrons, etc. This equation is sometimes written with g=2.

What is Curie law of paramagnetism?

According to the Curie law of paramagnetism, the strength of magnetization in any paramagnetic material varies inversely with the temperature applied to the material, which means the more the temperature of the paramagnetic material is, the lesser will be magnetization in the material.

What are the shortcomings of free electron theory?

1) It fails to explain the electrical conductivity of semiconductors and insulators. temperature. 3) It fails to explain the concept of specific heat of metals. 4) It fails to explain the mean free path of the electrons.

#### What are the failures of classical free electron theory?

Drawbacks of classical free electron theory 1) It fails to explain the electric specific heat and the specific heat capacity of metals. 2) It fails to explain superconducting properties of metals. 3) It fails to explain new phenomena like photo-electric effect, Compton effect, Black body radiation, etc.

What is Weiss theory of paramagnetism?

Weiss’ Theory (Domain theory of ferromag : According to weiss, a feromagnetic substance. contains atoms with permanent magnetic. moments, as in a paramagnetic substance, but due to special form of interaction.

What are paramagnetism and ferromagnetism?

Paramagnetism refers to materials like aluminum or platinum which become magnetized in a magnetic field but their magnetism disappears when the field is removed. Ferromagnetism refers to materials (such as iron and nickel) that can retain their magnetic properties when the magnetic field is removed.

## What is the basic cause of paramagnetism?

Paramagnetism is due to the presence of unpaired electrons in the material, so most atoms with incompletely filled atomic orbitals are paramagnetic, although exceptions such as copper exist. An external magnetic field causes the electrons’ spins to align parallel to the field, causing a net attraction.

What do you mean by paramagnetism?

/ (ˌpærəˈmæɡnɪˌtɪzəm) / noun. physics the phenomenon exhibited by substances that have a relative permeability slightly greater than unity and a positive susceptibility. The effect is due to the alignment of unpaired spins of electrons in atoms of the materialCompare diamagnetism, ferromagnetism.