Reversible change of charge ordering transition temperature in induced by electric pulses

Specific heats and magnetic moments of La 0.5 Ca 0.5 + x MnO 3 − y + Δ y polycrystalline ceramics were measured under different resistance states induced by electric pulses. Experimental results revealed that the specific heat associated with ferromagnetic spin waves had a larger value at a low resistance state compared to that at a high state, indicating the growth of ferromagnetic regions as the resistance changed from a high state to a lower one. The charge ordering temperature ( T CO ) at a low resistance state was higher than that at a high state, in contrast to the prediction based on the traditional double exchange model. We proposed that the ferromagnetic clusters at a low resistance state would cause a reduction of the collective Jahn–Teller distortion in the ferromagnetic phase, thus leading to an increase in T CO .