Modeling and design of hybrid semiconductor/magnetic circuits based on the interconversion between spin and charge currents and on the control of magnetic properties by electrical field

Published : 22 October 2019

Spin electronics is a merging of microelectronics and magnetism which aims at taking advantage of the best of the two worlds. Magnetism is very appropriate for memory functions since it allows encoding information in a nonvolatile way via the direction of magnetization of magnetic nanostructures. Magnetic memory called MRAM (Magnetic Random Access Memories) are about to be launched in volume production at several major microelectronics companies. For readout, this memory uses the magnetoresistance of magnetic tunnel junctions while the writing is performed by using the magnetic torque that a spin-polarized current exerts on the magnetization of a magnetic nanostructure (spin transfer torque). But spinelectronics keeps on progressing and new phenomena have been discovered since then on which our laboratory is actively working. These new phenomena rely on spin-orbit interactions and on the control of the magnetic properties of magnetic nanostructures by electric field rather than magnetic field or spin transfer torque. They enable the conception of memories and non-volatile logic circuits working at multiGHz frequency and exhibiting extremely low power consumption. The purpose of this internship will first consist in developing compact models of devices based on these new phenomena, for electrical simulation using the standard design suites of microelectronics. The models will be confronted to experimental results obtained in our laboratory and others available from literature. Once the models are validated, simple circuits will be designed based on these phenomena such as non-volatile standard cells for digital design, small memory matrix or radiofrequency spintronics oscillators, for which the implementation of these newly discovered phenomena seems particularly promising. These circuits’ performances will be benchmarked with those of equivalent circuits made from conventional semiconductor (CMOS) technology.

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