Random Fields and Random Anisotropies in the Mixed Ising-XYMagnetFexCo1−xTiO3

Abstract

We report a synchrotron x-ray scattering study of the phase transitions in the mixed Ising-XY magnets with quenched randomness: ${\mathrm{Fe}}_{x}{\mathrm{Co}}_{1\ensuremath{-}x}{\mathrm{TiO}}_{3}$ as a function of $x$ and, in the Ising regime, as a function of magnetic field. We observe at high resolution the loss of Ising order due either to the applied field on field cooling or to the ordering of the XY component after initial establishment of the Ising order on cooling. The latter is difficult to understand within our current picture of the random field Ising model. The XY phase has only short-range order due to random anisotropy effects.