Titanium-III warwickites: A family of one-dimensional disordered magnetic systems

We present x-ray, susceptibility, and magnetization (up to 18 T) measurements in the compound ${\mathrm{MgTiOBO}}_3$, which forms in the structure known as warwickite. This structure is characterized by the presence of ribbons along the c axis where the metallic ions are located. This system is magnetic since the Ti ions are in the valence state ${\mathrm{Ti}}^{3+}$ with the electronic configuration 3${\mathit{d}}^1$. Its susceptibility has a temperature dependence, at low temperatures, given by χ(T) ∝ ${\mathit{T}}^{\mathrm{-}\mathrm{\alpha }}$, with the exponent α≊0.83. The low-temperature behavior of the magnetization, as a function of field, is described by m ∝ ${\mathit{H}}^{\gamma }$ with γ≊1-α. These results, together with the x-ray measurements, allow us to identify this material as belonging to a family of inorganic, one-dimensional, disordered magnetic systems.