Coherent spin dynamics in the nonuniform ferromagnetic InGaAs/GaAs/$\delta$-Mn structures

A detailed study of the coherent spin dynamics of photoexcited carriers in a heterostructure with an InGaAs/GaAs quantum well and a $\delta$-Mn-layer separated from the quantum well by a 3–10 nm-thick GaAs spacer indicates its strong non-uniformity in the plane and mesoscopic separation to the regions of carrier localization. Mesoscopic separation with a characteristic scale of $\sim$100–200 nm is also observed using magnetic force microscopy below the Curie temperature of the $\delta$-Mn-layer.