Understanding the Curie Weiss Law: Magnetic Susceptibility and Temperature

Introduction to the Curie Weiss Law

The Curie Weiss Law provides a foundation for understanding magnetic susceptibility in materials at temperatures above the Curie point. According to this law, the magnetic susceptibility (χ) of a paramagnetic material is described as inversely proportional to the difference between the temperature (T) and the Curie temperature (Tc). This relationship is mathematically represented as:
χ = C / (T Tc)

Parameter usage:

• C (Curie constant) = specific to the material being studied, measured in Kelvin meters per Tesla square (K·m/T²).
• T (temperature) = absolute temperature of the material in Kelvin (K).
• Tc (Curie temperature) = the temperature at which a material's intrinsic magnetic moments change direction, measured in Kelvin (K).

Example valid values:

• C = 1.256
• T = 350
• Tc = 330

Output:

• χ (magnetic susceptibility) = unitless value indicating the material's response to an applied magnetic field.

Data validation:

Ensure the values of T are always greater than Tc. If T is not greater than Tc, the formula would result in an error as magnetic susceptibility skyrockets towards infinity or becomes undefined.

Real Life Example:

Imagine working in a physics lab that performs experiments on various magnetic materials. You have a piece of iron that you want to test for magnetic susceptibility at 350K. The Curie constant (C) for iron is approximately 3.5 K·m/T², and it has a Curie temperature (Tc) of 1043K. By applying the Curie Weiss Law:

χ = 3.5 / (350 1043)

You quickly realize that this value is invalid as T is smaller than Tc. However, adjusting the temperature parameter:

χ = 3.5 / (1200 1043) = 3.5 / 157 ≈ 0.0223

This resulting susceptibility tells you that under these conditions, the magnetic response of iron is minimal.

Summary

The Curie Weiss Law is a fundamental equation in understanding magnetism, depicting how the temperature and material constants govern magnetic behavior. Although straightforward, the equation clarifies how materials transition from paramagnetic to ferromagnetic as temperatures change, guiding material scientists and physicists in practical applications.

Tags: Physics, Magnetism, Curie-Weiss Law