1 Introduction 2 Magnetic Tunnel Junctions: A Route for CMOS/Magnetism Integration 3 Spin-Transfer Phenomenon 4 Magnetic Random Access Memories (MRAM) 4.1 Stoner-Wolfarth MRAM (SW-MRAM) 4.2 Toggle MRAM 4.3 Spin-Transfer Torque MRAM (STT-MRAM) 4.4 Thermally Assisted MRAM (TA-MRAM) 5 Racetrack Memories

I.L. Prejbeanu, R.C. Sousa, B. Dieny, J.-P. Nozieres, S. Bandiera, K. Mackay On paper, MRAMs combine non volatility, high speed, moderate power consumption, infinite endurance and radiation hardness, all at low cost and easy to embed. Since its inception in the late 90’s, however, and despite numerous promising announcements from laboratories, large corporations and start-ups, […]

A. Mejdoubi, G. Prenat, and B. Dieny Magnetic Tunnel Junction (MTJ) devices are CMOS compatible with high stability, high reliability and non-volatility. A macro-model of MTJ with precessional switching is presented in this paper. This model is based on Spin-Transfer Torque (STT) writing approach. The current-induced magnetic switching and excitations was studied in structures comprising […]

Spinelectronics is a very rapidly expanding area of R&D which merges magnetism and electronics (Nobel Prize 2007). Since the discovery of giant magneto-resistance (GMR) in 1988, several breakthroughs have further boosted this field [spin-valves 1990, tunnel magneto-resistance (TMR) 1995, spin-transfer 1996, voltage controlled magnetic properties 2004]. The phenomenon of spin-transfer is particularly attractive both from […]

Charge- and spin-diffusion equations, taking into account spin-diffusion and spin-transfer torque, were numerically solved using a finite element method in complex noncollinear geometry. As an illustration, this approach was used to study the spin-dependent transport in a two-dimensional model giant magnetoresistance metallic pillar sandwiched between extended electrodes as is the case in magnetoresistive heads for […]

A recent report from ITRS ERD/ERM working group has identified STT MRAM and RedoxRAM as the most promising candidates for emerging scalable and manufacturable non-volatile memories1. This paper is focused on MRAM. It explains how the heating produced by Joule dissipation around the tunnel barrier of magnetic tunnel junctions (MTJ) can be used to assist […]

This paper is focused on thermally assisted magnetic random access memories (TA-MRAMs). It explains how the heating produced by Joule dissipation around the tunnel barrier of magnetic tunnel junctions (MTJs) can be used advantageously to assist writing in MRAMs. The main idea is to apply a heating pulse to the junction simultaneously with a magnetic […]

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 cells aiming at sub-nanosecond switching and for sub-20nm technology nodes. Ultrafast precessional spin-transfer switching in elliptical magnetic tunnel junction […]

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 other technologies of non-volatile memories (FLASH, 105 cycles; PCRAM, 109 cycles; ReRAM, 1010 10 cycles). Combined with their speed (switching time 1-5ns), and density […]

B. Dieny, R.C. Sousa, J.P. Nozières, O. Redon, I.L. Prejbeanu, Magnetic Random Access Memories (Ch.28), in Nanoelectronic and Information Technology, R. Waser Ed., Wiley-VCH (2011). ISBN: 978-3-527-40927-3. Spinelectronics is a rapidly expanding area of research and development which merges magnetism and electronics (See Chapter 4 for insights on the related basics). Since the discovery of […]