Alternating current magnetotransport in Sm0.1La0.6Sr0.3MnO3

We report frequency dependent (f = 0.1 to 5 MHz) electrical resistivity in Sm0.1La0.6Sr0.3MnO3 in superimposed dc magnetic fields (H = 0–1 kOe). Resistive (ρ′) and reactive (ρ″) components of the complex resistivity (ρ = ρ′+iρ″) were measured simultaneously. With increasing f, both ρ′ and ρ′′ increase abruptly at the onset of ferromagnetic transition (Tc = 348 K) and exhibit an anomaly at T *≈ 147 K ≪ Tc in H = 0 kOe. The observed features in ρ′ and ρ′′ are depressed with increasing H leading to 35% magnetoresistance for ΔH = 300 Oe and f = 3 MHz. It is suggested that the frequency dependent magnetotransport is dominated by the field and frequency dependences of the ac permeability.