GdFe0.8Ni0.2O3 as a new multiferroic compound for low-voltage-driven spintronic devices

Shu-Jui Chang¹, Ming-Hang Chung¹, Shang-Fan Lee², Chao-Cheng Kaun³, Tetsuya Nakamura⁴, Yuan-Chieh Tseng^1*

¹Materials Science & Engineering, National Chiao Tung University, Hsin-chu, Taiwan
²Physics, Academia Sinica, Taipei, Taiwan
³Applied Science, Academia Sinica, Taipei, Taiwan
⁴Physics, Japan Synchrotron Radiation Research Institute (JASRI), Japan

* Presenter:Yuan-Chieh Tseng, email:yctseng21@mail.nctu.edu.tw

At the forefront of spintronics, electrical (voltage) control of magnetic devices will require novel materials to increase drive current capability, as well as lowering power consumption and promoting operating speed. Multiferroic devices are potentially suitable for application of electrical (voltage) controlled devices, owing to the coexistence of ferroelectric (FE) and magnetic orders in a single phase. Therefore, the idea of making spintronic devices based on multiferroic materials comes very naturally.

Unfortunately, development in the field of multiferroics is stagnating due to slow progress in the development of new multiferroic compounds. In this study, we demonstrated the use of sputtering to grow a new multiferroic thin film that features coupled FE and antiferromagnetic (AFM) orders at room temperature. The FE and magnetic orders of the film are very responsive to low applied voltages (+/- 1 volt) and the multiferroic behavior is sensitive to bias polarity. Combining this film with a Co ferromagnetic layer resulted in a heterostructure capable of generating discrete magnetic orders simply by altering the bias magnitude and bias sign.

Thus, this material could double the number of available magnetic read-out states within a low voltage regime, which satisfies the requirements for low-power and high-storage technology. Theoretical analysis and experiment results indicate the importance of Ni-dopant in regulating the polarity-dependent multiferroicity of this Gadolinium ferrite system. We believe that the development of such materials could open the door to new spintronic architectures that exploit the local gating of magnetic properties, thereby reducing the energy required for switching while increasing storage capacities.

Keywords: spintronics, multiferroics, voltage-control