Charge and spin transport across graphene and multifunctional oxide interfaces: towards energy-efficient logic and memory devices

Si Chen

Research output: ThesisThesis fully internal (DIV)

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Abstract

Since the invention of transistors in the mid-20th century, we have entered the Information Age. In this Age, information evolution is achieved by downscaling transistors. However, further downscaling leads to reaching the limits of miniaturization at atomic levels. Future information technologies in terms of both data storage and logic computing need to be developed. This thesis focuses on experimental fundamental research to further the knowledge about future electronics.
We report on the first observation of spin transport in graphene on TiO2-terminated SrTiO3 (STO) and find that surface electric dipoles and electric-field driven electronic and structural phase transitions unique to STO influence spin transport and spin relaxation in graphene. Further charge transport studies in graphene on STO imply an influence of the domain walls onto the potential landscape in graphene and find the anti-hysteresis are related to the movement of oxygen vacancies in STO, which in theory could be used for combined logic and memory. In addition, we have used spin Hall magnetoresistance and the spin Seebeck effect to read out the magnetic ordering in BiFeO3 (BFO) in two different strain states electrically. Finally, we report on the proximity effect in graphene/BFO hetero-structure by studying its magneto-transport, illustrating a strong influence of BFO local magnetic moment on spin transport in graphene. This finding opens a great opportunity for realizing spin logic devices by electric control.
We conclude that our studies yield new opportunities for utilizing proximity-induced functionalities at hetero-interfaces, which can be used to develop future spintronics and memristive applications.
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • University of Groningen
Supervisors/Advisors
  • Banerjee, Tamalika, Supervisor
  • van Wees, Bart, Supervisor
Award date5-Apr-2022
Place of Publication[Groningen]
Publisher
DOIs
Publication statusPublished - 2022

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