Magnetic Random Access Memories (MRAM) is a non-volatile memory technology, where information is stored by the magnetization direction of magnetic electrodes, very similar to computer hard-disk drives. The goal for MRAM memory is to simultaneously achieve high-speed read/write times, high density and unlimited cycling compared to other existing and emerging technologies.
Our group is developing advanced MRAM cell concepts patented at Spintec. The concepts are based on the use of temperature to reduce power consumption and increase the stability of the stored information. These ideas go beyond the conventional MRAM approach. The naturally occurring temperature increase during the write step is not lost, but is instead used to achieve the seemingly opposing goal of lowering the power consumption and increasing the thermal stability in the operating temperature range. Our group fosters young and experienced researchers developing/applying their expertise in the field of MRAM.
Questions to be addressed
Our main research axis is to use the naturally occurring temperature increase during the write step, when a current flows through the magnetic tunnel junction. The heating is used to go above a temperature threshold, making it possible to write the storage layer magnetization. This principle has been applied to in-plane magnetization cells using a storage layer pinned by an anti-ferromagnet and recently to perpendicular anisotropy cells. Our group’s goal is to demonstrate the proof-of-concept and then improve MRAM cell properties.
Our work involves the development of magnetic material systems, nano-fabrication (20-200nm cells), characterization of devices (magnetic & electrical) and simulation of the device behavior. Our activity in these vast fields is as follows;: On materials research, we are developing magnetic tunnel junctions with in-plane and perpendicular magnetic anisotropy. New electrode stacks having the material properties required by each specific concept need to be integrated in magnetic tunnel junctions, while achieving high levels of TMR signal. For the characterization of each concept we determine the write window parameters in terms of magnetic field, power consumption and magnetization reversal dynamics. Macrospin and micromagnetic simulation provide a better physical understanding of the system properties and the possibilities for optimization.
ANR EXCALYB – Perpendicular Anisotropy Materials for High-Density Non-volatile Magnetic Memory Cells
Crocus R&D – Thermally assisted MRAM
- MRAM WITH SOFT REFERENCE LAYER: IN-STACK COMBINATION OF MEMORY AND LOGIC FUNCTIONS [July 02nd, 2015]
Q. Stainer, L. Lombard, K. Mackay, R. C. Sousa, I. L. Prejbeanu, B. Dieny This paper describes an original concept of thermally assisted MRAM in which memory and logic functions are combined in the same stack. ...
- MRAM CONCEPTS FOR SUB-NANOSECOND PRECESSIONAL SWITCHING AND SUB-20NM CELL SCALING [July 02nd, 2015]
R.C. Sousa, S. Bandiera, M. Marins de Castro, B. Lacoste, L. San-Erneterio-Alvarez, L. Nistor, S. Auffret, U. Ebels, C. Ducruet, I. L. Prejbeanu, L. Vila, B. Rodrnacq, B. Dieny This work reports on advances in MRAM ...
- WP1 : RELIABILITY AND IMPROVED PERFORMANCES OF SPINTRONIC MATERIALS [July 02nd, 2015]
In WP1, studies were conducted to understand the mechanisms responsible for the dielectric breakdown in magnetic tunnel junctions (MTJs). A key asset of STT-MRAM is their write endurance which is much better than in all ...
- THERMALLY ASSISTED MAGNETIC MEMORIES (TA-MRAM) [July 02nd, 2015]
M. Kerekes, C. Papusoi, C. Ducruet, O. Redon, R. Sousa, L. Prejbeanu, B. Dieny Magnetic random access memories (MRAM) have been the first attempt to realize a Spintronics based technology. The information is stored in the ...
- SPIN TRANSFER TORQUE WRITING IN THERMALLY ASSISTED MAGNETIC MEMORIES [July 02nd, 2015]
J. Hérault, M. Souza, Y. Hadj-Larbi, M-T. Delaye, R. Sousa, L. Prejbeanu, B. Dieny Spin transfer torque (STT) switching in magnetic random access memories (MRAM) is the most power efficient method to write information in MRAM ...