Electron spin resonance in Ge0.99Mn0.01 nanowires

Electron spin resonance (ESR) is measured in arrays of Ge_0.99Mn_0.01 nanowires (NWs). We show that the ESR spectrum comprises four lines corresponding to the different magnetic subsystems. Two lines are attributed to spin-wave excitations in the Mn⁺³ ion subsystem. The third component corresponds to the resonance in the Mn⁺² ions. The last component has an asymmetric Dyson form and characterizes the resonance in the mobile paramagnetic centers. We demonstrate that temperature dependences of ESR parameters are correlated in subsystems of the localized magnetic centers (Mn⁺³ and Mn⁺² ions) and delocalized band carriers. It implies the presence of exchange interactions between the localized Mn ions and spin-polarized carriers.