Lu14Co3In3-type Y14Co3Al3, Gd14Co3.2Al2.8, {Gd, Tb, Dy, Lu}14Ni3Al3 and {Tb, Dy}14Co3Al3 compounds: Crystal structure, magnetic properties and heat capacity

The crystal structure of new Lu₁₄Co₃In₃-type {Gd, Tb, Lu}₁₄Ni₃Al₃ compounds (P4₂/nmc. N 137, tP80) has been established using powder X-ray diffraction studies with cell parameters a = 0.95765(2) nm, c = 2.30214(5) nm for Gd₁₄Ni₃Al₃, a = 0.95012(5) nm, c = 2.28190(10) nm for Tb₁₄Ni₃Al₃ and a = 0.92604(2) nm, c = 2.23350(4) nm for Lu₁₄Ni₃Al₃. Magnetic properties of the polycrystalline Y₁₄Co₃Al₃, Gd₁₄Co_3.2Al_2.8 and {Tb, Dy}₁₄{Co, Ni}₃Al₃ have been studied by magnetization measurements. Y₁₄Co₃Al₃ is paramagnetic down to 2 K, Gd₁₄Co_3.2Al_2.8 exhibits ferro-antiferromagnetic ordering, while {Tb, Dy}₁₄{Co, Ni}₃Al₃ show field sensitive pure antiferromagnetic ordering with field induced slight ferromagnetism. Heat capacity measurements (in zero applied magnetic field and field of 50 kOe) confirm metamagnetic-like transitions of Tb₁₄Ni₃Al₃ and Dy₁₄Ni₃Al₃.