Freezing of short-range ordered antiferromagnetic clusters in the CrFeTi₂O₇ system

We report on the CrFeTi$_2$O$_7$ (CFTO) system using a combination of x-ray diffraction, dc magnetization, ac susceptibility, specific heat and neutron diffraction measurements. CFTO is seen to crystallize in a monoclinic $P21/a$ symmetry. It shows a glassy freezing at $T{_f}$ ~ 22 K, characterized by the observation of bifurcation between ZFC and FC ${\chi}$ (T) curves, frequency dispersion across $T{_f}$ in ac susceptibility, appearance of non-zero remanent magnetization and coercivity below $T{_f}$, very slow relaxation of iso-thermal remanent magnetization with time and a linear temperature dependence of magnetic contribution to specific heat $C{_m}$ below $T{_f}$. The microscopic neutron diffraction analysis of CFTO not only confirms the absence of long-range antiferromagnetic ordering but also exhibits diffuse scattering due to the presence of shortrange ordered antiferromagnetically correlated spin clusters.