High exchange anisotropy and high blocking temperature in strongly textured NiFe(111)/FeMn(111) films

Choe, G.; Gupta, Subhadra

doi:10.1063/1.118650

Cited by 70 publications

(31 citation statements)

References 14 publications

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“…In the Mn-based system, the above-mentioned critical condition for the appearance of H EX was rarely observed in the AFM layer thickness dependence of H EX 33,34) and was not evident at all in its temperature dependence. Instead, the temperature dependences of H EX in other exchange-biased systems have often shown that H EX gradually decreases with increasing temperature and nally becomes zero at the blocking temperature [35][36][37][38][39] . This trend occurs because the thermal agitation of the AFM magnetization dominates the temperature dependence of the exchange bias.…”

Section: Perpendicular Exchange Bias Induced By Cr 2 O 3 (0001)mentioning

confidence: 99%

Perpendicular Exchange Bias and Magneto-Electric Control Using Cr2O3(0001) Thin Film

Shiratsuchi

Nakatani

2016

Mater. Trans.

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Antiferromagnets themselves do not generate either stray elds or spontaneous magnetization. However, if an antiferromagnet is coupled with a ferromagnet, unique and useful characteristics appear. Exchange bias is one such characteristic that is utilized in spintronic devices like spin-valve lms. To date, exchange bias has been used to induce static effects in devices; however, the exchange bias has not been switchable in these devices. Recently, switchable exchange bias has been developed using Cr 2 O 3 , which exhibits a magnetoelectric effect in an antiferromagnetic layer. The promising features of this effect are (1) the strength of the exchange bias is high and its direction is perpendicular to the lm, and (2) the switching is triggered by an electric eld. In this overview, we will summarize our recent results on the unique temperature dependence of high, perpendicular exchange bias and magnetoelectric switching of the induced perpendicular exchange bias.

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Section: Perpendicular Exchange Bias Induced By Cr 2 O 3 (0001)mentioning

confidence: 99%

Perpendicular Exchange Bias and Magneto-Electric Control Using Cr2O3(0001) Thin Film

Shiratsuchi

Nakatani

2016

Mater. Trans.

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“…1). A Ta underlayer serves as a buffer, and the NiFe texturing layer provides a (111) texture 12 for the FeMn layer. The NiFe film on top of AF FeMn layer together with a thin Co polarizing layer represent the fixed layer of the spin valve.…”

Section: Methodsmentioning

confidence: 99%

“…The system has intensively been studied in order to optimize H EB and to explore the relation between magnetic properties, microstructure, and interface roughness. [10][11][12][13][14] …”

Section: Introductionmentioning

confidence: 99%

Rotating-field magnetoresistance of exchange-biased spin valves

Paul

Büchmeier

Bürgler

et al. 2004

Journal of Applied Physics

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We investigate the magnetoresistance (MR) of spin valves by (i) varying the strength of the field applied in a fixed direction and (ii) rotating the field with fixed strength. The latter data reflect in general a mixture of giant and anisotropic magnetoresistance (GMR and AMR). We present an experimental procedure to suppress the AMR contributions of all ferromagnetic layers in the spin valve without disturbing the GMR response. The resulting angular MR curves are fitted with a single-domain model to determine with high precision the exchange bias field, the uniaxial anisotropies, the GMR ratio, and the interlayer coupling field. The application of the method to differently prepared Ta͑5.0 nm͒ / NiFe͑3.0 nm͒ / FeMn͑15.5 nm͒ / NiFe͑3.0 nm͒ /Co͑2.0 nm͒ / Cu͑3.5 nm͒ /Co͑2.0 nm͒ / NiFe͑7.0 nm͒ spin valves with GMR ratios of 1.8% and 4% demonstrates the sensitivity and reveals differences of the order of a few percents of the exchange bias field for the uniaxial anisotropy fields of the free and pinned layer as well as for the interlayer coupling field.

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“…Since the blocking temperature of the CoFe/FeMn SV is different from that of IrMn/CoFe SV [5,8], the exchange coupling orientation of T3.1.4…”

Section: Resultsmentioning

confidence: 99%

“…Magnetization states (7) and (10) in which the magnetizations of the free FM and pinned FM layers are in anti-parallel alignment in the bottom IrMn/CoFe SV while they are in parallel alignment in the top CoFe/FeMn SV, are corresponding to the magnetoresistance state (c). Magnetization states (3), (6), (8), and (11), in which the magnetizations of the free FM and pinned FM layers are in parallel alignment both in the top CoFe/FeMn SV and bottom IrMn/CoFe SV, are corresponding to the same magnetoresistance state (d).…”

Section: Resultsmentioning

confidence: 99%

Multilevel Magnetoresistance in a Structure Consisting of two spin-valves

Qiu

et al. 2001

MRS Proc.

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The magnetic and electrical properties as well as the structural characteristics have been studied on a series of samples with structure substrate (Sub)/SV(I)/A1 2 0 3 5nm/SV(2). Here, SV(l) 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/CoFe l.5/Cu2.6/CoFe2/FeMn 10/Ta5 top SV and SV(2) is Ta5/NiFe2/CoFe l.5(or 2)/Cu2.6/CoFe2/IrMn8/Ta5 top SV. SV(1) and SV(2) in the structure are decoupled by a A1 2 0 3 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 /A120 3 5ffa5/NiFe2/CoFe2/Cu2.6/CoFe2/IrMn8fTa5, 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 IT under high vacuum because of different interlayer coupling fields (H.,t) 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/CoFe 1.5/Cu2.6/CoFe2/FeMn 0/Ta5/AI 2 0 3 5/Ta5/NiFe2/CoFe I.5/Cu2.6/CoFe2 /lrMn8/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.

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High exchange anisotropy and high blocking temperature in strongly textured NiFe(111)/FeMn(111) films

Cited by 70 publications

References 14 publications

Perpendicular Exchange Bias and Magneto-Electric Control Using Cr<sub>2</sub>O<sub>3</sub>(0001) Thin Film

Perpendicular Exchange Bias and Magneto-Electric Control Using Cr<sub>2</sub>O<sub>3</sub>(0001) Thin Film

Rotating-field magnetoresistance of exchange-biased spin valves

Multilevel Magnetoresistance in a Structure Consisting of two spin-valves

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