Observation of the spin-charge thermal isolation of ferromagnetic Ga₀.₉₄Mn₀.₀₆As by time-resolved magneto-optical measurement

الأصل · EN

The dynamics of magnetization under femtosecond optical excitation is studied in a ferromagnetic semiconductor Ga₀.₉₄Mn₀.₀₆As with a time-resolved magneto-optical Kerr effect measurement with two color probe beams. The transient reflectivity change indicates the rapid rise of the carrier temperature and relaxation to a quasi-thermal equilibrium within 1 ps, while a very slow rise of the spin temperature of the order of 500ps is observed. This anomalous behavior originates from the thermal isolation between the charge and spin systems due to the spin polarization of carriers (holes) contributing to ferromagnetism. This constitutes experimental proof of the half-metallic nature of ferromagnetic Ga₀.₉₄Mn₀.₀₆As arising from double exchange type mechanism originates from the d-band character of holes.