Inverse magnetoelectric effects at the nanoscale for MRAM applications
Leuven | More than two weeks ago
Magnetic memories are presently intensely researched for embedded memory applications. Especially magnetic random-access memory (MRAM) has recently been started to be commercialized in consumer appliances and it can be expected that it will become broadly used in the near future. In such magnetic memories, the information is stored in the orientation of the perpendicular magnetization in a magnetic tunnel junction. The resistance of the tunnel junction is used to read the information whereas spin-transfer torque is used to write the information. To improve the performance of the cell and to open new application fields, both the read and write speed of the MRAM cells need to be improved without affecting the memory retention.
To date, much research is being devoted to improving the write performance of MRAM cells using e.g. spin-orbit torques or voltage-controlled magnetic anisotropies. By contrast, rather little attention has been paid to the read performance of MRAM cells. To improve the read performance, voltage-based schemes using magnetoelectric materials and compounds appear promising. In recent years, magnetoelectricity has seen a renaissance due to technological and theoretical progress and its research has focused on manipulating magnets by electric fields for both memory and logic applications. In such applications, magnetoelectricity promises much higher power efficiency than conventional charge-spin conversion by spin-transfer or spin-orbit torques. Concerning the opposite challenge of spin-charge conversion, little attention has been devoted to inverse magnetoelectric effects as read mechanism in memory devices so far.
Within this thesis, the student will study the inverse magnetoelectric effects to generate voltage signals based on the magnetization control of a nanomagnet. The work will make use of innovative (e.g. piezomagnetic, magnetocapacitive) materials and concentrate on the fundamental understanding of the magnetoelectric coupling towards nanoscale. To this aim, the student will fabricate and electrically characterize test devices to quantify the coupling and deduce its relation to materials properties. The results will allow for an evaluation of the prospects of inverse magnetoelectricity for disruptive read mechanisms and pave the way for applications in future magnetic memories. The student should have a strong interest in nanofabrication in a cleanroom environment as well as in leading edge research topics on magnetism and magnetic materials. The work will be in close collaboration with experimentalists working on integration of magnetoelectrics into spintronic devices for exploratory logic and memory.
Type of project: Combination of internship and thesis, Thesis, Internship
Duration: 6 Months
Required degree: Master of Science, Master of Engineering Technology, Master of Engineering Science
Required background: Physics, Nanoscience & Nanotechnology, Materials Engineering, Electrotechnics/Electrical Engineering
Supervising scientist(s): For further information or for application, please contact: Christoph Adelmann (Christoph.Adelmann@imec.be) and Florin Ciubotaru (Florin.Ciubotaru@imec.be)