Ferrites are ceramic magnetic materials.
They are generally oxides containing iron oxide with other metal oxides.
Nickel zinc ferrite is commonly written as:
\[
Ni-Zn\ \text{ferrite}.
\]
It is a soft magnetic material.
Soft ferrites are materials which can be easily magnetized and demagnetized.
They have low coercivity and are used in high-frequency applications such as transformer cores, inductors, and electronic devices.
Hard ferrites have high coercivity and are used as permanent magnets.
Nickel zinc ferrite belongs to the soft ferrite group.
Therefore, the correct answer is:
\[
\text{Soft Ferrite}.
\]