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Title: A multi-state magnetic memory dependent on the permeability of Metglas

A three-state magnetic memory was developed based on differences in the magnetic permeability of a soft ferromagnetic media, Metglas 2826MB (Fe{sub 40}Ni{sub 38}Mo{sub 4}B{sub 18}). By heating bits of a 250 nm thick Metglas film with 70–100 mW of laser power, we were able to tune the local microstructure, and hence, the permeability. Ternary memory states were created by using lower laser power to enhance the initial permeability through localized atomic rearrangement and higher power to reduce the permeability through crystallization. The permeability of the bits was read by detecting variations in an external 32 Oe probe field within 10 μm of the media via a magnetic tunnel junction read head. Compared to data based on remanent magnetization, these multi-permeability bits have enhanced insensitivity to unexpected field and temperature changes. We found that data was not corrupted after exposure to fields of 1 T or temperatures of 423 K, indicating the effectiveness of this multi-state approach for safely storing large amounts of data.
Authors:
; ; ; ; ; ;  [1] ;  [2] ;  [3]
  1. U.S. Army Research Laboratory, 2800 Powder Mill Rd, Adelphi, Maryland 20783 (United States)
  2. National Institute of Standards and Technology, 100 Bureau Dr, Gaithersburg, Maryland 20899 (United States)
  3. Spin Transfer Technologies, 33 Arch St, Boston, Massachusetts 02110 (United States)
Publication Date:
OSTI Identifier:
22398856
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 14; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BORON ALLOYS; COMPARATIVE EVALUATIONS; CRYSTALLIZATION; FILMS; HEATING; IRON ALLOYS; MAGNETIC SUSCEPTIBILITY; MAGNETIZATION; MICROSTRUCTURE; MOLYBDENUM ALLOYS; NICKEL ALLOYS; PERMEABILITY; TEMPERATURE DEPENDENCE; TUNNEL EFFECT