Magnetic Field-Induced Insulator-to-Metal Transition in Perovskite Manganites Eu_1-ϰSr_ϰMnO₃

The perovskite manganites Eui_1-ϰSr_ϰMnO₃ are semiconductors although they exhibit ferromagnetic behavior around ϰ = 0.40. There is no evidence that charge ordering occurs. In an applied magnetic field of 15kOe, however, the specimens with ϰ = 0.40 and 0.45 become the metallic conductors below their respective Curie temperatures of 75 K and 80 K. This magnetic field-induced insulator-to-metal transition leads a change in the resistivity exceeding 10⁶ at 12 K. The transition is irreversible with respect to the magnetic field. The possibility of a field-induced phase transition having a lower symmetry than that at room temperature (orthorhombic) is in consideration.