Capacitive Torque Magnetometry: Study of field-induced magnetic transitions and transient states in the Spin-Ice Material Ho₂Ti₂O₇

We used capacitive torque magnetometry to compile phase diagrams that show the field-induced magnetic transitions between specific spin textures of the spin ice state. High quality single crystals have been measured at 500 mK in applied fields up to 11 T applied along various crystallographic directions. Utilizing reported results from neutron scattering as our starting point we have developed a phenomenological model that fully characterizes the anisotropic magnetic phase diagram of the system. This model clearly shows the evolution of the spin textures between the previously identified Q = 0, Q = X, and 3-in/1-out states, and it shows the existence of transient states between them. These transient states are characterized by spin flip excitations taking the spin ice away from the well-defined spin textures. Activation energies associated with these excitations have been extracted. This study demonstrates the applicability of torque magnetometry in probing specific spin textures hosted by the spin ice state.