Single-crystalline samples of a new Zintl compound, Eu 3Ga 2P 4, have been synthesized by a Ga-flux method. Eu 3Ga 2P 4 is found to crystallize in a monoclinic unit cell, space group C2/c, isostructural to Ca 3Al 2As 4. The structure is composed of a pair of edge-shared GaP 4 tetrahedra, which link by corner-sharing to form Ga 2P 4 two-dimensional layers, separated by Eu 2+ ions. Magnetic susceptibility showed a Curie-Weiss behavior with an effective magnetic moment consistent with the value for Eu 2+ magnetic ions. Below 15 K, ferromagnetic ordering was observed and the saturation magnetic moment was 6.6 μ B. Electrical resistivity measurements on a single crystal showed semiconducting behavior. Resistivity in the temperature range between 280 and 300 K was fit by an activation model with an energy gap of 0.552(2) eV. The temperature dependence of the resistivity is better described by the variable-range-hopping model for a three-dimensional conductivity, suggesting that Eu-P bonds are involved in the conductivity. A large magnetoresistance, up to -30%, is observed with a magnetic field H = 2 T at T = 100 K, suggesting strong coupling of carriers with the Eu 2+ magnetic moment.
ASJC Scopus subject areas
- Inorganic Chemistry
- Physical and Theoretical Chemistry