Crystal Structure and a Giant Magnetoresistance Effect in the New Zintl Compound Eu3Ga2P4

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• 作者：Naohito Tsujii ; Catherine A. Uvarov ; Peter Klavins ; Tanghong Yi ; Susan M. Kauzlarich
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：March 5, 2012
• 年：2012
• 卷：51
• 期：5
• 页码：2860-2866
• 全文大小：417K
• 年卷期：v.51,no.5(March 5, 2012)
• ISSN：1520-510X

文摘

Single-crystalline samples of a new Zintl compound, Eu₃Ga₂P₄, have been synthesized by a Ga-flux method. Eu₃Ga₂P₄ is found to crystallize in a monoclinic unit cell, space group C2/c, isostructural to Ca₃Al₂As₄. The structure is composed of a pair of edge-shared GaP₄ tetrahedra, which link by corner-sharing to form Ga₂P₄ two-dimensional layers, separated by Eu²⁺ ions. Magnetic susceptibility showed a Curie鈥揥eiss behavior with an effective magnetic moment consistent with the value for Eu²⁺ magnetic ions. Below 15 K, ferromagnetic ordering was observed and the saturation magnetic moment was 6.6 渭_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鈥揚 bonds are involved in the conductivity. A large magnetoresistance, up to 鈭?0%, is observed with a magnetic field H = 2 T at T = 100 K, suggesting strong coupling of carriers with the Eu²⁺ magnetic moment.