The Ni-Zn synthetic ferrite were acquired from thermally decomposing the metal nitrates Fe(NO$_3$)$_3$.$9H_2$O, Zn($NO_3$)$_2$.$6H_2$O, Ni($NO_3$)$_2$. $6H_2$O, and Cu($NO_3$)$_2$. $3H_2$O at $150^{circ}C$ for 24 hours and was calcined at $500^{circ}C$. Each of those was pulverized for 3, 6, 9, and 12 hours in a steel ball mill and was sintered between $700^{circ}C$ and $1,000^{circ}C$ for 1 hour, and then their microstructures and electromagnetic properties were examined. We could make the initial specimens chemically bonded in liquid at the temperature as low as $150^{circ}C$, by using the melting points less than $200^{circ}C$ of the metal nitrates instead of the mechanical ball milling, then narrowed a distance between the particles into a molecular level, and thus lowed sintering temperature by at least $200^{circ}C$ to$ 300^{circ}C$. Their initial permeability was 50 to 400 and their saturation magnetic induction density and coercive force 2,400 G and 0.3 Oe to 0.5 Oe each, which were similar to those of Ni- Zn ferrite synthesized in the conventional process. In the graph of initial permeability vs frequencies, we could observe a $180^{circ}C$rotation of the magnetic domain, which appears in a broad band of microwave near the resonance frequency