Crystal structure and magnetic properties of novel intermetallic compounds in the Er–Cu–Ga system

Three new ternary gallides have been found in the Er–Cu–Ga ternary system. Their crystal structure, as well as that of the previously reported ErCu0.5Ga1.5, has been refined from single crystal X-ray diffraction data. ErCu2−xGax (0.4 ≤ x ≤ 0.7) crystallizes in the CaIn2 structure-type (space group P63/mmc), ErCu5−xGax (0.8 ≤ x ≤ 2.3) in the CaCu5-type (space group P6/mmm), ErCu12−xGax (5.7 ≤ x ≤ 6.7) in the ThMn12-type (space group I4/mmm) and Er14Cu51−xGax (5.5 ≤ x ≤ 11.0) in the Gd14Ag51-type (space group P6/m). Magnetic measurements show Curie–Weiss paramagnetic behavior down to 2 K for these four phases.