ATL>Magnetic properties and magnetic structure of HoTiGe and ErTiGe.

We have studied the crystal structure, magnetic structure and magnetic properties of the tetragonal compounds HoTiGe and ErTiGe by means of neutron diffraction and magnetic measurements. The neutron-diffraction measurements were made in the range from 1.7 K to temperatures above the corresponding magnetic-ordering temperatures (TN=88 and 41 K, respectively). Both compounds have a simple antiferromagnetic structure with a propagation vector q=(0, 0, 0.5). The Ho moments have a preferred moment direction along the tetragonal c-axis at all temperatures in the magnetically ordered regime, while the direction is perpendicular to the c-axis for the Er moments. This difference in easy moment direction has been discussed in terms of a crystal-field-induced rare-earth-sublattice anisotropy. The magnetic measurements showed that both compounds give rise to metamagnetic transitions in their magnetically ordered states. This field-induced transition is particularly pronounced in HoTiGe where it is accompanied by a strong hysteresis in the lower-temperature range. [Copyright &y& Elsevier]