SINGLE-CRYSTAL MAGNETIC-PROPERTIES AND THE CRYSTAL-FIELD INTERACTIONSOF ER3+ IN ERVO4

Crystals of erbium vanadate were flux-grown and magnetic measurements carried out on the single crystals for the first time in the temperatu re range 300-13.2 K. At room temperature chi(parallel to) > chi(perpen dicular to); a cross-over in Delta chi is observed at about 130 K. Our magnetic data and that of Kuse on crystal field excitations were anal yzed invoking an effective crystal held of D-2d symmetry; the theoreti cal values provide an excellent agreement to the observed data. The pr incipal susceptibility (chi(perpendicular to)) did not show any sharp change in its behavior down to 13.2 K, which rules out a structural or magnetic phase transition in this range. The computed Stark energies led us to locate a Schottky anomaly in the electronic heat capacity. T he quadrupole splitting of Er-167 due to crystal field effects has bee n computed; the hyperfine heat capacity displays a sharp peak at about 4.8 mK. (C) 1997 Elsevier Science Ltd.