Influence of Ge concentration on magnetic properties of \(\hbox {Co}_{(1-x)} \hbox {Ge}_{x}\) thin films

Cobalt-rich \(\hbox {Co}_{(1-x)} \hbox {Ge}_{x}\) alloy thin films with various Ge concentrations (up to \({x} = 0.09\)) have been investigated by vibrating sample magnetometry and ferromagnetic resonance techniques to understand the influence of Ge doping on magnetostatic and magnetodynamic properties. Room-temperature magnetization curves have shown that the addition of Ge atoms can reduce the saturation magnetization in a fast manner. Utilizing a conventional ferromagnetic resonance setup, the out-of-plane angular dependencies of the resonance spectra have been measured and data have been analyzed using a computer program to simulate the magnetic behavior of the thin-film alloys. The experimental findings demonstrate that the magnetic properties of \(\hbox {Co}_{(1-x)} \hbox {Ge}_{x}\) alloys can be precisely adjusted by varying the Ge content. Both the g-factor and the Gilbert-damping parameter show correlated changes, highlighting the tunability of these magnetic characteristics. This ability to modify saturation magnetization and damping parameters by altering the Ge concentration enables the optimization and customization of the alloy for specific applications in spintronic devices.