Magnetic contribution to the resistivity noise in a La0.7Sr0.3MnO3 film grain boundary - art. no. 132407

Magnetoresistance and resistivity-noise measurements have been performed on a La0.7Sr0.3MnO3 film deposited on a bicrystal substrate with a misorienta tion angle of 8.2 degrees. The zero field 1/f resistivity noise was investi gated at temperatures below the ferromagnetic transition temperature and a detailed study of its field dependence was performed at low temperature, yi elding information relating to the magnetic microstructure close to the gra in-boundary region. A field dependence of the noise level similar to that o f the de resistance is evidenced. The corresponding noise spectra exhibit i n addition to the 1/f noise a Lorentzian contribution. This contribution is attributed to thermally activated domain wall motion occurring at fields c lose to the coercivity. and is connected to the multidomain magnetic state neighboring the grain-boundary region.