Anomalous magnetic ordering of Ce and Kondo-like effect in the double-exchange ferromagnet(Pr0.1Ce0.4Sr0.5)MnO3

Abstract

We report evidence for the occurrence of a Kondo-like effect and anomalous magnetic ordering of cerium in a double-exchange ferromagnet $({\mathrm{Pr}}_{0.1}{\mathrm{Ce}}_{0.4}{\mathrm{Sr}}_{0.5}){\mathrm{MnO}}_{3}.$ Neutron-diffraction measurements show that this material undergoes a first-order transition from an orthorhombic $(\mathrm{Imma})$ to a tetragonal $(I4/mcm)$ structure that is accompanied by a ferromagnetic transition, as temperature decreases. At about 250 K, a bulk ferromagnetic metallic transition occurs below which the manganese moments remain ordered ferromagnetically down to 1.5 K. Below $T=100\mathrm{K},$ the Ce moments are ordered antiferromagnetically with respect to the ferromagnetic Mn moments and thus form a ferrimagnetic ground state. The temperature dependence of resistivity $\ensuremath{\rho}(T)$ shows anomalous behavior; it increases with decrease of temperature and shows a maximum at $T\ensuremath{\sim}120\mathrm{K}$ and a minimum at $T\ensuremath{\sim}15\mathrm{K}$ in contrast to the metallic behavior expected due to larger W and the double-exchange ferromagnetism. This behavior of resistivity and the antiferromagnetic ordering of cerium with the ferromagnetic Mn moments suggest a Kondo-like effect in a spin-polarized conduction-electron system.