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Keywords:

  • Crystal growth;
  • Magnetic properties;
  • Intermetallic phases;
  • Gallium

Abstract

The single crystals of two polymorphs of LnNiGa4, namely, the orthorhombic α-LnNiGa4 (Ln = Y, Gd–Yb) and, a new polymorph, the tetragonal β-LnNi1–xGa4 (Ln = Tb–Er), were successfully grown by using the self-flux method. α-LnNiGa4 (Ln = Y, Gd–Yb) is isostructural to YNiAl4 and can be described as an edge-sharing polyhedral of Ni@Ga7Ln2 (Ln = Y, Gd–Yb) along the ac-plane that is sandwiched between the square nets of the Ga atoms along the b-axis. The structure of β-LnNi1–xGa4 (Ln = Tb–Er) is a distorted variant of the Ce2NiGa10-structure type with a Ni deficiency and multiple Ga split positions and is structurally related to YNiGa3Ge. The magnetic data for β-LnNi1–xGa4 (Ln = Tb–Er) and the transport properties for α-LnNiGa4 (Ln = Y, Gd–Tm) and β-LnNi1–xGa4 (Ln = Tb–Er) are reported. Antiferromagnetic correlations are observed in the magnetic susceptibility of β-LnNi1–xGa4 (Ln = Tb–Er), where the magnetic transitions occurred below 7 K and with effective moments that are consistent with free Ln3+ ions.