Synthesis, characterization and magnetic properties of LnBO 3 (Ln ≡ Nd, Gd, Tb, Dy, Ho and Er)

Abstract

A new method for the synthesis of some lanthanide orthoborates LnBO 3 (Ln ≡ Nd, Gd, Tb, Dy, Ho and Er) has been successfully used. The different orthoborates LnBO 3 were obtained by mixing metal hydroxides Ln(OH) 3 and orthoboric acid B(OH) 3 in stoichiometric amounts at low temperatures between 873 and 973 K and at pressures of between 10 −4 and 10 −5 mm Hg. The results seem to indicate that this method of synthesis can be applied to the isolation of metal borates at temperatures that are several hundreds of degrees below those reported in the literature. The characterization of these materials has been carried out by X-ray powder diffraction and IR spectrometry. The magnetic susceptibilities of these orthoborates have also been measured in the temperature range 4.2–300 K. From 50 to 300 K the data fit a Curie-Weiss behaviour and the Weiss constants are negative for all the compounds. Magnetic susceptibility shows a quasi-Curie-like behaviour for GdBO 3.