Dear Hafiz Usman Khalid,

As discussed by Soraya Gavazzi and Sam Allardyce, the following discussion could also help you:

Mathematically, the dielectric permittivity is a complex quantity. When we say complex quantity, there are two parts; the real and imaginary parts. Physically, the real part is called the dielectric constant (ε′); the imaginary part is called dielectric loss (ε″). But it is still not enough to understand the physics of dielectric constant and dielectric loss (ε″). For more simplify their physics, we can use the dielectric constant to point out the storage of energy or the material's polarizing ability. Whereas, we can use the dielectric loss to point out the loss of energy in a material. Now, for any materials, the ratio between the dielectric loss and dielectric constant is called dielectric loss tangent, tan δ = ε″/ε′.

Our three papers could help you:

1- Article Electrical and dielectric properties of meridional and facia...

2-Article Effect of thermal treatment on the structural, electrical, a...

3- Article Structural characterizations and electrical conduction mecha...

Best Wishes

Abdu

Thanks for your valuable answers

Sam Allardyce Soraya Gavazzi Abdu Saeed