Question

Choose the graph that best describes the variation of dielectric constant (\( \epsilon_r \)) with temperature (\( T \)) in a ferroelectric material. 
(T\(_C\) is the Curie temperature) 

• A. \( \epsilon_r \) increases sharply and then decreases near \( T_C \).
• B. \( \epsilon_r \) jumps discontinuously at \( T_C \).
• C. \( \epsilon_r \) increases continuously after \( T_C \).
• D. \( \epsilon_r \) decreases sharply as \( T \) increases.

Hint:

The Curie temperature marks the transition from ferroelectric to paraelectric behavior, characterized by a peak in the dielectric constant.

Answer 1

The Correct Option is A

In ferroelectric materials, the dielectric constant \( \epsilon_r \) typically exhibits a sharp peak at the Curie temperature \( T_C \).

Step 1: As the temperature approaches \( T_C \) from below, \( \epsilon_r \) increases sharply, reaching a maximum value at \( T_C \).

Step 2: Above \( T_C \), the dielectric constant starts decreasing rapidly, indicating the loss of ferroelectric properties and transition to a paraelectric state.
This behavior is best represented by graph (A).