Spin rotation in ErGa3

The magnetic phase diagram of ErGa3, built up from bulk magnetisation data, shows in zero-applied magnetic field two successive transitions at T1=2.6 and T2 congruent with 2.8 K, respectively. The magnetic ordering of ErGa3 examined by neutron diffraction, can be derived from the so-called {((1)/(2)), ((1)/(2)), 0} structure, i.e. one in which the successive antiparallel (1 1 0) sheets of spins have additionally superimposed on them a sinusoidal modulation parallel to the [1 0 0] axis. The temperature dependence of neutron diffraction diagrams studied on the single crystal, revealed in the range of (2.6-2.78) K an abrupt reorientation of the Er3+ spins from the nearly [1 1 0] direction, towards the [1 0 0] axis. In this way previously observed effect on the polycrystalline sample has been confirmed. This rotation can be attributed to the T1 transition found in the H-T magnetic phase diagram