Pseudobrookite ${\mathrm{Fe}}_2{\mathrm{TiO}}_5$ single crystal with highly disordered $\mathrm{F}{\mathrm{e}}^{3+}/\mathrm{T}{\mathrm{i}}^{4+}$ occupation was successfully grown using the floating zone technique. The bifurcation of zero-field cooling and field cooling curves of the dc magnetic susceptibilities and the frequency-dependent shift of the ac magnetic susceptibilities exhibits distinct longitudinal spin freezing in ${\mathrm{Fe}}_2{\mathrm{TiO}}_5$ at $T_L\sim 35$ K. The existence of the cluster spin glass state was observed in ${\mathrm{Fe}}_2{\mathrm{TiO}}_5$ below $T_L$. Additionally, the frequency dispersion behavior of dielectric permittivity indicates the existence of the cluster dipolar glass state in ${\mathrm{Fe}}_2{\mathrm{TiO}}_5$. The observed nonzero magnetodielectric effect and the magnetic field dependent dynamic magnetoelectric coefficient reveal a correlated behavior between these two glass states, showing that ${\mathrm{Fe}}_2{\mathrm{TiO}}_5$ is a rare multiglass magnetoelectric coupling material. Notably, large and anisotropic remnant electric polarization was found, where $\mathrm{\Delta }{\mathit{P}}_{c-\mathrm{axis}}\sim -1.6\times {10}^4\mu \mathrm{C}{\mathrm{m}}^{-2}$ and $\mathrm{\Delta }{\mathit{P}}_{b-\mathrm{axis}}\sim 3.5\times {10}^4\mu \mathrm{C}{\mathrm{m}}^{-2}$ at $T=10$ K. But the sign of $\mathrm{\Delta }\mathit{P}$ was not reversed by the electric field, implying that ${\mathrm{Fe}}_2{\mathrm{TiO}}_5$ is a pyroelectric material. Our research further demonstrates that the highly distorted FeO6 octahedron induces the anisotropic $\mathrm{\Delta }\mathit{P}$ and the multiglass state, suggesting that clusters of spin glass and dipolar glass coexist in the same region in ${\mathrm{Fe}}_2{\mathrm{TiO}}_5$.

Close

PrevNext

View figure in article

• Glass transition
• Magnetoelectric effect
• Spin glasses
• Transition metal oxides
• Dielectric spectroscopy
• Susceptibility measurements