Magnetic Properties of Some Rare Earth-Aluminum Alloys

Abstract

The RAl alloys are orthorhombic; the structure can be described with a trigonal motif similar to a half‐cell of CsCl. The R₃Al₂ alloys are tetragonal. The magnetic properties of the RAl alloys, where R is any rare earth from Ce to Tm, and those of the R₃Al₂ alloys, with R passing from Gd to Tm, have been measured in fields up to 25 kOe or 60 kOe and at temperatures between 1.4° and 400°K. The RAl alloys, with R from Pr to Tb, order antiferromagnetically at temperature between 20°K (PrAl) and 72°K (TbAl); the magnetic configuration of TbAl has been studied by neutron diffraction; HoAl is ferromagnetic with a Curie point at 26°K; DyAl, ErAl and TmAl exhibit metamagnetism at 4.2°K. Gd₃Al₂ is ferromagnetic with a Curie point at 282°K, close to that of Gd; Dy₃Al₂ shows an antiferromagnetic transition near 20°K in zero field and metamagnetic behavior induced by a field below this temperature; its Curie point is 76°K. All compounds exhibit a Curie‐Weiss behavior above their transition points, with a paramagnetic moment close to that of the corresponding free tripositive rare earth ions.