Enhanced Magnetic Modulation In Hfo2-Based Resistive Memory With An Hf Top Electrode

Magnetic modulation in binary-oxide-based resistive random access memory (RRAM) shows promise for applications in future electronics. However, the small magnetization change and large operating voltage in undoped binary oxide films make its practical applications difficult. In this study, we investigated magnetic switching behaviors in RRAM devices based on HfO2 film utilizing either Ti or Hf as the top electrode (TE). Substantially enhanced magnetic modulation and reduced operating voltage of the HfO2 film is demonstrated in the device using an Hf TE. The saturation magnetization of the HfO2 film is more than four times larger in a low resistance state than in a high resistance state under a set/reset voltage of only 0.4/0.3 V. We propose that these results are related to two factors: the high standard Gibbs energy of oxide formation for metal Hf; and the dual ion diffusion of hafnium (originating from the Hf TE) and oxygen in the device. This work shows that selecting a suitable TE can result in enhanced capability for electrical control of magnetism in metal oxides. Published by AIP Publishing.