Four resistance states in La$_{0.7}$Sr$_{0.3}$MnO$_{3}$/(Ba, Sr)TiO$_{3}$/La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ multiferroic tunnel junction at room temperature

Multiferroic tunnel junction (MFTJ), composed of two ferromagnetic electrodes separated by a thin ferroelectric barrier, has been predicted to serve as a four-state device as a result of the coexistence of tunneling magnetoresistance and tunneling electroresistance effects. Our previous results have demonstrated such devices, but only at low temperatures. Here, we report a MFTJ composed of La$_{0.7}$Sr$_{0.3}$MnO$_{3}$/(Ba, Sr)TiO$_{3}$/La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ fabricated by pulsed-laser deposition. A typical R-H loop with a sharp-switched resistance states (magnetic parallel and antiparallel) similar to that of magnetic tunnel junctions has been observed up to room temperature. Upon polarization reversal of the barrier, both the parallel and antiparallel resistances will switch to a different value. Clear tunneling magnetoresistance and tunneling electroresistance, hence the four-resistance states, have been observed at room temperature. The resistance states can be switched between them by electric and magnetic fields and the manipulation of the states will be discussed.