Transport Behavior in Spinel Oxide MgTi₂O₄

Spinel oxide MgTi₂O₄ is synthesized by the spark plasma sintering method. The temperature dependences of magnetic susceptibility and resistance are measured and investigated in detail. It is shown that the transition of MgTi₂O₄ occurs at the phase transition temperature T_t～258 K. The fits of resistance versus temperature curve demonstrate that MgTi₂O₄ displays metal behavior above T_t, while a dual conducting mechanism, the Mott-insulator-like variable range hopping and normal activated conduction, is suggested to be responsible for the transport behavior of MgTi₂O₄ below T_t.