Magnetism dynamics driven by phase separation in Pr-doped manganite thin films: A ferromagnetic resonance study

We performed ferromagnetic resonance measurements of a (La1-xPrx)(1)-yCayMnO3-delta with x = 0.52 +/- 0.05, y = 0.23 +/- 0.04, and delta = 0.14 +/- 0.10 thin single crystalline film which, in combination with micromagnetic simulations, reveal three temperature regions consistent with (i) a ferromagnetic-paramagnetic transition in which ferromagnetic domains nucleate and grow, (ii) followed by a filamentary fluidlike percolation of magnetic domains exhibiting dynamic processes and finally, iii) the existence of a blocking temperature below which the magnetism is a metastable glassy-like state with strong decoherence of the uniform resonance mode. Our results suggest a strain-liquid to strain-glass spin order transition in which the magnetism and fluidlike dynamics of the separated phases freeze at low temperatures. We show the magnetism dynamics depend strongly on the phase-separated state and morphology of the magnetic domains suggesting a route to control of phase separation and realization of spintronic and magnonic devices.