Single crystal growth and physical properties of the new ternary compound Eu2Mg4Si3

We have studied the magnetic and electrical properties of new ternary europium magnesium silicide Eu2Mg4Si3. The single crystalline Eu2Mg4Si3 has been prepared by the Mg self-flux method. The compound crystalizes in the hexagonal Hf2Co4P3-type structure with space group P6¯2m with unit cell parameters a=14.78(3)Å and c=4.434(6)Å. Magnetic, electrical, and thermal properties indicate that the system undergoes two successive phase transitions, occurring at TN1=9.6K and TN2=8.4K. The estimated effective magnetic moment is close to the moment of free Eu2+ ion. The electrical resistivity data ρ(T) for Eu2Mg4Si3 show a metallic-like behavior from room temperature down to about 100 K. However, the ρ(T) data exhibit a notable upturn below 80 K and a maximum around TN1 and then suddenly decrease with decreasing temperature. These features are strongly suppressed by applying magnetic fields and a metallic temperature dependence eventually exhibits over the whole temperature range in a magnetic field of 30 kOe. Such behavior is observed in some magnetoresistive compounds.