Multilevel magnetoresistance in a structure consisting of two spin-valves

Kebin Li; Yihong Wu; Jinjun Qiu; Guchang Han; Zaibing Guo; Towchong Chong

doi:10.1557/proc-674-t3.1

Multilevel magnetoresistance in a structure consisting of two spin-valves

Kebin Li, Yihong Wu^*, Jinjun Qiu, Guchang Han, Zaibing Guo, Towchong Chong

^*Corresponding author for this work

Research output: Contribution to journal › Conference article › peer-review

Abstract

The magnetic and electrical properties as well as the structural characteristics have been studied on a series of samples with structure substrate (Sub)/SV(1)/Al₂O₃5nm/SV(2). Here, SV(1) is either CoFe/IrMn based spin-valve (SV) such as Ta5/NiFe2/IrMn8/CoFe2/Cu2.6/CoFe2/Ta5 (thicknesses are in nanometers) bottom SV or Ta5/NiFe2/CoFe1.5/Cu2.6/CoFe2/FeMn10/Ta5 top SV and SV(2) is Ta5/NiFe2/CoFe1.5(or 2)/Cu2.6/CoFe2/IrMn8/Ta5 top SV. SV(1) and SV(2) in the structure are decoupled by a Al₂O₃ layer with 5nm in the magnetic properties, however, they are in parallel connection in the electrical properties. In a sample with structure Sub/Ta5/NiFe2/IrMn8/CoFe2/Cu2.6/CoFe2/Ta5 /Al₂O₃5/Ta5/NiFe2/CoFe2/Cu2.6/CoFe2/IrMn8/Ta5, five magnetoresistance states which are related to five magnetization states have been observed after the sample was annealed at T=220°C with a field strength of 1T under high vacuum because of different interlayer coupling fields (H_int) in the top and bottom CoFe/IrMn based SV_S (H_int is about 12.21 Oe in the top CoFe/IrMn SV and 29.3 Oe in the bottom CoFe/IrMn based SV). In a sample with structure Sub/Ta5/NiFe2/CoFe1.5/Cu2.6/CoFe2/FeMn10/Ta5/Al₂O₃5/Ta5/Ni Fe2/CoFe1.5/Cu2.6/CoFe2/IrMn8/Ta5, since the blocking temperature of the CoFe/FeMn based SV (T_b is about 150°C) is lower than that of CoFe/IrMn based SV (T_b is about 230°C), the spins can be easily engineered and therefore various magnetoresistance states can be obtained when the sample is magnetically annealed at different temperatures in a proper annealing sequence. By properly selecting materials and controlling the magnetically annealing conditions, multilevel giant magnetoresistance (MR) magnetic random access memory (MRAM) cell can be realized, which will significantly improve the MRAM data storage density without increasing any additional processing complexity.

Original language	English (US)
Pages (from-to)	T3.1.1-T3.1.6
Journal	Materials Research Society Symposium - Proceedings
Volume	674
DOIs	https://doi.org/10.1557/proc-674-t3.1
State	Published - 2001
Externally published	Yes
Event	Applications of Ferromagnetic and Optical Materials, Storage and Magnotoelectronics - San Francisco, CA, United States Duration: Apr 16 2001 → Apr 20 2001

ASJC Scopus subject areas

Condensed Matter Physics
Mechanics of Materials
Mechanical Engineering
General Materials Science

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10.1557/proc-674-t3.1

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@article{08a23df56d71472ba63c92733b833052,

title = "Multilevel magnetoresistance in a structure consisting of two spin-valves",

abstract = "The magnetic and electrical properties as well as the structural characteristics have been studied on a series of samples with structure substrate (Sub)/SV(1)/Al2O35nm/SV(2). Here, SV(1) is either CoFe/IrMn based spin-valve (SV) such as Ta5/NiFe2/IrMn8/CoFe2/Cu2.6/CoFe2/Ta5 (thicknesses are in nanometers) bottom SV or Ta5/NiFe2/CoFe1.5/Cu2.6/CoFe2/FeMn10/Ta5 top SV and SV(2) is Ta5/NiFe2/CoFe1.5(or 2)/Cu2.6/CoFe2/IrMn8/Ta5 top SV. SV(1) and SV(2) in the structure are decoupled by a Al2O3 layer with 5nm in the magnetic properties, however, they are in parallel connection in the electrical properties. In a sample with structure Sub/Ta5/NiFe2/IrMn8/CoFe2/Cu2.6/CoFe2/Ta5 /Al2O35/Ta5/NiFe2/CoFe2/Cu2.6/CoFe2/IrMn8/Ta5, five magnetoresistance states which are related to five magnetization states have been observed after the sample was annealed at T=220°C with a field strength of 1T under high vacuum because of different interlayer coupling fields (Hint) in the top and bottom CoFe/IrMn based SVS (Hint is about 12.21 Oe in the top CoFe/IrMn SV and 29.3 Oe in the bottom CoFe/IrMn based SV). In a sample with structure Sub/Ta5/NiFe2/CoFe1.5/Cu2.6/CoFe2/FeMn10/Ta5/Al2O35/Ta5/Ni Fe2/CoFe1.5/Cu2.6/CoFe2/IrMn8/Ta5, since the blocking temperature of the CoFe/FeMn based SV (Tb is about 150°C) is lower than that of CoFe/IrMn based SV (Tb is about 230°C), the spins can be easily engineered and therefore various magnetoresistance states can be obtained when the sample is magnetically annealed at different temperatures in a proper annealing sequence. By properly selecting materials and controlling the magnetically annealing conditions, multilevel giant magnetoresistance (MR) magnetic random access memory (MRAM) cell can be realized, which will significantly improve the MRAM data storage density without increasing any additional processing complexity.",

author = "Kebin Li and Yihong Wu and Jinjun Qiu and Guchang Han and Zaibing Guo and Towchong Chong",

year = "2001",

doi = "10.1557/proc-674-t3.1",

language = "English (US)",

volume = "674",

pages = "T3.1.1--T3.1.6",

journal = "Materials Research Society Symposium - Proceedings",

issn = "0272-9172",

publisher = "Materials Research Society",

note = "Applications of Ferromagnetic and Optical Materials, Storage and Magnotoelectronics ; Conference date: 16-04-2001 Through 20-04-2001",

}

TY - JOUR

T1 - Multilevel magnetoresistance in a structure consisting of two spin-valves

AU - Li, Kebin

AU - Wu, Yihong

AU - Qiu, Jinjun

AU - Han, Guchang

AU - Guo, Zaibing

AU - Chong, Towchong

PY - 2001

Y1 - 2001

N2 - The magnetic and electrical properties as well as the structural characteristics have been studied on a series of samples with structure substrate (Sub)/SV(1)/Al2O35nm/SV(2). Here, SV(1) is either CoFe/IrMn based spin-valve (SV) such as Ta5/NiFe2/IrMn8/CoFe2/Cu2.6/CoFe2/Ta5 (thicknesses are in nanometers) bottom SV or Ta5/NiFe2/CoFe1.5/Cu2.6/CoFe2/FeMn10/Ta5 top SV and SV(2) is Ta5/NiFe2/CoFe1.5(or 2)/Cu2.6/CoFe2/IrMn8/Ta5 top SV. SV(1) and SV(2) in the structure are decoupled by a Al2O3 layer with 5nm in the magnetic properties, however, they are in parallel connection in the electrical properties. In a sample with structure Sub/Ta5/NiFe2/IrMn8/CoFe2/Cu2.6/CoFe2/Ta5 /Al2O35/Ta5/NiFe2/CoFe2/Cu2.6/CoFe2/IrMn8/Ta5, five magnetoresistance states which are related to five magnetization states have been observed after the sample was annealed at T=220°C with a field strength of 1T under high vacuum because of different interlayer coupling fields (Hint) in the top and bottom CoFe/IrMn based SVS (Hint is about 12.21 Oe in the top CoFe/IrMn SV and 29.3 Oe in the bottom CoFe/IrMn based SV). In a sample with structure Sub/Ta5/NiFe2/CoFe1.5/Cu2.6/CoFe2/FeMn10/Ta5/Al2O35/Ta5/Ni Fe2/CoFe1.5/Cu2.6/CoFe2/IrMn8/Ta5, since the blocking temperature of the CoFe/FeMn based SV (Tb is about 150°C) is lower than that of CoFe/IrMn based SV (Tb is about 230°C), the spins can be easily engineered and therefore various magnetoresistance states can be obtained when the sample is magnetically annealed at different temperatures in a proper annealing sequence. By properly selecting materials and controlling the magnetically annealing conditions, multilevel giant magnetoresistance (MR) magnetic random access memory (MRAM) cell can be realized, which will significantly improve the MRAM data storage density without increasing any additional processing complexity.

AB - The magnetic and electrical properties as well as the structural characteristics have been studied on a series of samples with structure substrate (Sub)/SV(1)/Al2O35nm/SV(2). Here, SV(1) is either CoFe/IrMn based spin-valve (SV) such as Ta5/NiFe2/IrMn8/CoFe2/Cu2.6/CoFe2/Ta5 (thicknesses are in nanometers) bottom SV or Ta5/NiFe2/CoFe1.5/Cu2.6/CoFe2/FeMn10/Ta5 top SV and SV(2) is Ta5/NiFe2/CoFe1.5(or 2)/Cu2.6/CoFe2/IrMn8/Ta5 top SV. SV(1) and SV(2) in the structure are decoupled by a Al2O3 layer with 5nm in the magnetic properties, however, they are in parallel connection in the electrical properties. In a sample with structure Sub/Ta5/NiFe2/IrMn8/CoFe2/Cu2.6/CoFe2/Ta5 /Al2O35/Ta5/NiFe2/CoFe2/Cu2.6/CoFe2/IrMn8/Ta5, five magnetoresistance states which are related to five magnetization states have been observed after the sample was annealed at T=220°C with a field strength of 1T under high vacuum because of different interlayer coupling fields (Hint) in the top and bottom CoFe/IrMn based SVS (Hint is about 12.21 Oe in the top CoFe/IrMn SV and 29.3 Oe in the bottom CoFe/IrMn based SV). In a sample with structure Sub/Ta5/NiFe2/CoFe1.5/Cu2.6/CoFe2/FeMn10/Ta5/Al2O35/Ta5/Ni Fe2/CoFe1.5/Cu2.6/CoFe2/IrMn8/Ta5, since the blocking temperature of the CoFe/FeMn based SV (Tb is about 150°C) is lower than that of CoFe/IrMn based SV (Tb is about 230°C), the spins can be easily engineered and therefore various magnetoresistance states can be obtained when the sample is magnetically annealed at different temperatures in a proper annealing sequence. By properly selecting materials and controlling the magnetically annealing conditions, multilevel giant magnetoresistance (MR) magnetic random access memory (MRAM) cell can be realized, which will significantly improve the MRAM data storage density without increasing any additional processing complexity.

UR - http://www.scopus.com/inward/record.url?scp=0035559708&partnerID=8YFLogxK

U2 - 10.1557/proc-674-t3.1

DO - 10.1557/proc-674-t3.1

M3 - Conference article

AN - SCOPUS:0035559708

SN - 0272-9172

VL - 674

SP - T3.1.1-T3.1.6

JO - Materials Research Society Symposium - Proceedings

JF - Materials Research Society Symposium - Proceedings

T2 - Applications of Ferromagnetic and Optical Materials, Storage and Magnotoelectronics

Y2 - 16 April 2001 through 20 April 2001

ER -

Multilevel magnetoresistance in a structure consisting of two spin-valves

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