NDLI: Numerical analysis of a novel MTJ stack for high readability and writability

Content Provider	IEEE Xplore Digital Library
Author	Raychowdhury, A. Augustine, C. Somasekhar, D. Tschanz, J. Roy, K. De, V.
Copyright Year	2011
Description	Author affiliation: Circuit Research Lab, Intel Corporation, Hillsboro, OR, USA (Raychowdhury, A.; Somasekhar, D.; Tschanz, J.; De, V.) \|\| Dept of ECE, Purdue University, IN, USA (Augustine, C.; Roy, K.)
Abstract	Recent advances in non-volatile spin transfer torque (STT)-RAM technology, which stores data by the spin orientation of a soft ferromagnetic material and shows current induced switching, have created interest for its use as embedded memory [1–2]. When a spin-polarized current passes through a mono-domain ferromagnet, the ferromagnet absorbs some of the angular momentum of the electrons. It creates a torque that causes a flip in the direction of magnetization in the ferromagnet. This is used in magnetic tunneling junction (MTJ) based spin torque transfer (STT) RAM cells where a thin insulator (MgO) is sandwiched between a fixed ferromagnetic layer (polarizer) and the free layer (storage node). Depending on the direction of the current flow (perpendicular to these layers in our study), the magnetization of the free layer is switched to a parallel (P: low resistance state) or anti-parallel (AP: high resistance state) state. The study in this abstract is done for the 22nm technology node (temp: 85°C) for a storage area of 2F×F in a $6F^{2}$ cell. Typical MTJ stacks employed for use in STTRAMs comprise of ferromagnetic or synthetic Antiferromagnetic (for higher stability) free layers with a single or double MgO barrier (SBFF and DBSAF) (Fig. 1a, b). In the authors' previous work the use of double MgO for better writability and single MgO for better readability has been shown. In this paper, we propose a novel bidirectional MTJ stack (Fig. 1) with antiparallel fixed layers (DBSAF-AP) that inherits the high readability of a single barrier stack with better writability than a double barrier stack by employing an intermediate metastable ferromagnetic state (Fig. 2 — to be described later). By using a self-consistent NEGF (for transport) and LLG (for magnetic dynamics) simulation framework [2,4] we show readability, writability and scalability of the proposed stack.
Starting Page	347
Ending Page	350
File Size	538234
Page Count	4
File Format	PDF
ISBN	9781457707070
ISSN	19308876
e-ISBN	9781457707087
e-ISBN	9781457707063
DOI	10.1109/ESSDERC.2011.6044163
Language	English
Publisher	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Publisher Date	2011-09-12
Publisher Place	Finland
Access Restriction	Subscribed
Rights Holder	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subject Keyword	Switches Magnetic tunneling Magnetization Torque Tunneling magnetoresistance Switching circuits Current density
Content Type	Text
Resource Type	Article

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1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
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