Observation of higher-order harmonics in AF2 phase of NdCu2

The orthorhombic intermetallic compound NdCu2 orders antiferro-magnetically and exhibits three different antiferromagnetic phases AF1, AF2 and AF3 in zero magnetic field below T-N = 6.5 K. The intermediate phase AF2, which is stable only in a very narrow temperature range, can be characterised by wave vector tau' = (3/5 + epsilon a epsilon b 0), epsilon a approximate to epsilon b approximate to 0.003. This means that a number of magnetic reflections, corresponding to higher-order harmonics of tau', can be observed in h-k plane. In this paper we present the experimental data showing the higher-order harmonics up to 61 tau'.