where
c
is called the material’s magnetic susceptibility. In an isotropic material (magnetic properties are
not direction dependent),
c
is a scalar quantity, and the magnetization and field vectors are proportional
and aligned. In anisotropic material (magnetic properties depend on direction),
c
is a tensor represented
by a 3
´
3 matrix; therefore, the magnetization vector magnitude and direction depend on the direction
and strength of the inducing field. As a result, the magnetization vector will not always align with the
magnetization inducing field vectors. Equation 48.5 can be modified for magnetically “soft” material to
the following: