Properties of HoVO ₄ below 1 K I. Predictions from nuclear magnetic resonance

Abstract

The size of the internal field in HoVO 4 has been determined by n. m. r. measurements (Bleaney et al . 1978); the interactions between the Ho 3+ ions are mainly dipolar, with a small contribution from antiferromagnetic exchange. It is shown that these measurements can be used directly to calculate the interactions between the enhanced 165 Ho nuclear moments. These interactions are used to predict the nature of the nuclear spin arrangement in the ordered state, and it is shown that a whole range of ‘puckered’ four sub-lattice arrangements all have the same energy. The results are similar to those for a purely dipolar antiferromagnet, with a Néel temperature of 4.8 mK. The sign of the nuclear electric quadrupole interaction is discussed, and the lattice contribution is compared with that deduced by Cook & Cashion (1979) for GdVO 4 .