A Kondo-like transport was observed in a metal-semiconductor transition (MSC) at low temperatures in the ferromagnetic metallic phase of the perovskite manganites. Experimental data can be best fitted in the framework of Kondo scattering, electron-electron $\left(e\text{−}e\right)$, and electron-phonon $\left(e\text{−}p\right)$ interaction. The results show that this behavior depends strongly on the content of the spin-glass phase and can be tuned with an applied magnetic field, which can be explained by the spin disorder scattering of electrons and/or antiferromagnetic cluster on a nanoscale and/or microscale, the interaction and strong correlation between electrons, and antiferromagnetic background. For the undoped samples, the MSC transition means the existence of intrinsic spin disorder with magnetic inhomogeneity. It is important that the present results give a direct evidence of Kondo scattering in ferromagnetic metallic manganites and prove that Kondo anomaly appears not only in metals containing small amounts of magnetic impurities but also in ferromagnetic conducting compounds containing spin-disorder clusters. This could be a general characteristic of the strongly correlated electron systems.

• Received 17 March 2005

DOI:https://doi.org/10.1103/PhysRevB.72.054410