Re-entrant spin glass and magnetoresistance in Co0.2Zn0.8Fe1.6Ti0.4O4 spinel oxide

We have investigated the static and dynamical response of magnetic clusters in Co0.2Zn0.8Fe1.6Ti0.4O4 spinel oxide, where a sequence of magnetic states, i.e., paramagnetic to ferromagnetic state at TC⩽270 K and ferromagnetic to canted spin glass (CSG) state at Tf⩽125 K are observed. The time dependence of remanent magnetization shows nonequilibrium spin dynamics in the CSG state, whereas a weak time dependent relaxation is observed in the ferromagnetic state. There is no relaxation effect in the paramagnetic state. The field dependence of the magnetization confirms the absence of long range ferromagnetic order in the system. We considered the magnetic clusters as ferromagnetic domains, in which the spins are not necessarily infinite ordered due to spin canting effects. The variation of the ferromagnetic and antiferromagnetic components and magnetic disorder inside the clusters shows some interesting magnetic and electrical properties in the system, viz. field induced transition in M vs H data, re-entrant ...