Question

What is Curie law?

Hint:

A simple way to remember Curie's law: Heat causes chaos. In magnetism, this "chaos" (thermal agitation) disrupts the orderly alignment of magnetic dipoles. More heat (higher T) leads to more chaos and thus weaker magnetic properties (lower \(\chi_m\)).

Answer 1

Step 1: Understanding the Concept:
Curie's law describes the magnetic behavior of paramagnetic materials in relation to temperature. Paramagnetic materials are weakly attracted to magnetic fields. This attraction is due to the presence of unpaired electrons, which act as tiny magnetic dipoles.
Step 2: Key Formula or Approach:
The law is mathematically expressed in terms of magnetic susceptibility (\(\chi_m\)) or magnetization (\(M\)).
The magnetic susceptibility \(\chi_m\) is defined as the ratio of the intensity of magnetization (\(M\)) to the magnetic field intensity (\(H\)).
Curie's Law states:
\[ \chi_m \propto \frac{1}{T} \] or \[ \chi_m = \frac{C}{T} \] where:
- \(\chi_m\) is the magnetic susceptibility.
- \(T\) is the absolute temperature in Kelvin.
- \(C\) is a material-specific constant called the Curie constant.
Step 3: Detailed Explanation:
In paramagnetic materials, the atomic dipoles are randomly oriented due to thermal agitation. When an external magnetic field is applied, it tends to align these dipoles, causing a net magnetization.
However, the thermal energy of the atoms opposes this alignment. As the temperature increases, thermal agitation becomes stronger, making it harder for the external field to align the dipoles. Consequently, the material's ability to be magnetized (its susceptibility) decreases.
Curie's law quantifies this relationship, stating that the susceptibility is inversely proportional to the absolute temperature. This means that if you double the absolute temperature, you halve the magnetic susceptibility of a paramagnetic substance, assuming the applied field is not too strong.
Step 4: Final Answer:
Curie's law is a fundamental principle in magnetism that relates the magnetic susceptibility of a paramagnetic material to its absolute temperature, showing they are inversely proportional.