Violation of the Mooij rule in ferromagnetic composites Co$_x$(CuO)$_{100-x}$ and Co$_x$(Al$_2$O$_3$)$_{100-x}$

It is demonstrated that the Mooij rule is violated for the composites Co$_x$(CuO)$_{100-x}$ and Co$_x$(Al$_2$O$_3$)$_{100-x}$ with $x>40$ (%), namely, the resistance of these systems does not tend to saturation, as their temperature increases and reaches $300\div7000$ μ$\Omega\cdot$cm, which is many imeslthe value of $\rho^*\approx150$ μ$\Omega\cdot$cm, with the temperature resistance coefficient remaining positive. The violation of the Mooij rule is associated with an important role played by intergranular contacts in the resistance growth.