The spin ice Ho(2)Ti(2)O(7) versus the spin liquid Tb(2)Ti(2)O(7): field-induced magnetic structures.

We studied the field-induced magnetic structures of Ho(2)Ti(2)O(7) spin ice by means of single-crystal neutron diffraction with a magnetic field applied along a [110] direction. These structures are compared to those of the spin liquid Tb(2)Ti(2)O(7) previously measured in similar experimental conditions. For both compounds, magnetic structures of two types with k = 0 and k = (0, 0, 1) propagation vectors coexist at low temperature (1.6 K) and high applied field (7 T). The k = 0 structures are described by the basis functions of the same irreducible representation for both Tb(2)Ti(2)O(7) and Ho(2)Ti(2)O(7). On the other hand, the k = (0, 0, 1) structures of Tb(2)Ti(2)O(7) and Ho(2)Ti(2)O(7) correspond to different irreducible representations, leading to different magnetic structures.