Influence of seed layer on the magnetoresistance properties in IrMn-based magnetic tunnel junctions

Chen, Weibin; Hao, Runrun; Lu, Shengfu; Cao, Zhiqiang; Yan, Shaohua; Yan, Suying; Zhu, Dapeng; Leng, Qunwen

doi:10.1016/j.jmmm.2021.168674

Cited by 5 publications

(4 citation statements)

References 43 publications

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“…[TaN] shows the most significant increase, but still suitable for MgO-MTJ growth. In addition, MTJ buffers are also required to have a low resistivity [39] for compatibility with the patterning process and high TMR ratio [40]. The overall lower H ex , H c and T b values obtained with [TaN], are most likely due to its larger surface roughness.…”

Section: Effect Of Buffer Layers On Mnir/cofe Bilayersmentioning

confidence: 99%

Engineering buffer layers to improve temperature resilience of magnetic tunnel junction sensors

et al. 2023

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Improving the thermal resilience of magnetic tunnel junctions (MTJs) broadens their applicability as sensing devices and is necessary to ensure their operation under harsh environments. In this work, we are address the impact of temperature on the degradation of the magnetic reference in ﬁeld sensor stacks based on MgO-MTJs. Our study starts by simple MnIr/CoFe bilayers to gather enough insights into the role of critical morphological and magnetic parameters and their impact in the temperature dependent behavior. The exchange bias coupling ﬁeld (Hex), coercive ﬁeld (Hc), and blocking temperature (Tb) distribution are tuned, combining tailored growth conditions of the antiferromagnet (AFM) and different buffer layer materials and stackings. This is achieved by a unique combination of ion beam deposition and magnetron sputtering, without vaccum break. Then, the work then extends beyond bilayers into more complex state-of-the-art MgO MTJ stacks as those employed in commercial sensing applications. We systematically address their characteristic ﬁelds, such as the width of the antiferromagnetic coupling plateau ΔH, and study their dependence on temperature. Although, [Ta/CuN] buffers showed higher key performance indications (e.g. Hex) at room temperature in both bilayers and MTJs, [Ta/Ru] buffers showed an overall wider ΔH up to 200 ºC, more suitable to push high temperature operations. This result highlights the importance of properly design a suitable buffer layer system and addressing the complete MTJ behaviour as function of temperature, to deliver the best stacking design with highest resilience to high temperature environments.

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Section: Effect Of Buffer Layers On Mnir/cofe Bilayersmentioning

confidence: 99%

Engineering buffer layers to improve temperature resilience of magnetic tunnel junction sensors

et al. 2023

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“…Introducing a third element is one viable approach to improving the thermal stability of CoFe alloys [14]. CoFe thin films find widespread applications in magnetic materials and magnetic storage systems [15,16]. However, the addition of Sm elements may further enhance their performance, including improvements in magnetic and structural properties [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Surface Roughness-Induced Changes in Important Physical Features of CoFeSm Thin Films on Glass Substrates during Annealing

Fern,

Liu,

Chang

et al. 2023

Materials

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Co60Fe20Sm20 thin films were deposited onto glass substrates in a high vacuum setting. The films varied in thickness from 10 to 50 nm and underwent annealing processes at different temperatures: room temperature (RT), 100, 200, and 300 °C. Our analysis encompassed structural, magnetic, electrical, nanomechanical, adhesive, and optical properties in relation to film thickness and annealing temperature. X-ray diffraction (XRD) analysis did not reveal characteristic peaks in Co60Fe20Sm20 thin films due to insufficient growth-driving forces. Electrical measurements indicated reduced resistivity and sheet resistance with increasing film thickness and higher annealing temperatures, owing to hindered current-carrier transport resulting from the amorphous structure. Atomic force microscope (AFM) analysis showed a decrease in surface roughness with increased thickness and annealing temperature. The low-frequency alternating current magnetic susceptibility (χac) values increased with film thickness and annealing temperature. Nanoindentation analysis demonstrated reduced film hardness and Young’s modulus with thicker films. Contact angle measurements suggested a hydrophilic film. Surface energy increased with greater film thickness, particularly in annealed films, indicating a decrease in contact angle contributing to this increase. Transmittance measurements have revealed intensified absorption and reduced transmittance with thicker films. In summary, the surface roughness of CoFeSm films at different annealing temperatures significantly influenced their magnetic, electrical, adhesive, and optical properties. A smoother surface reduced the pinning effect on the domain walls, enhancing the χac value. Additionally, diminished surface roughness led to a lower contact angle and higher surface energy. Additionally, smoother surfaces exhibited higher carrier conductivity, resulting in reduced electrical resistance. The optical transparency decreased due to the smoother surface of Co60Fe20Sm20 films.

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“…NiFe/IrMn is one of the exchange biased systems widely applied in planar Hall sensors [30,31], magnetic tunnel junction devices [32,33], microwave integrated circuits [34,35], strain sensors [36], flexible and shapeable electronics [37,38]. The interfacial spin configuration of the AF layers is very sensitive to structural defects, that facilitates bending strain tailored exchange bias [39,40], successfully implemented in wrinkled NiFe/IrMn thin films [37], grown on flexible substrates.…”

Section: Introductionmentioning

confidence: 99%

Thermal hysteresis of magnetization in NiFe/IrMn exchange-biased ferromagnet

Таланцев¹,

Bakhmetiev²,

Моргунов³

2022

J. Phys. D: Appl. Phys.

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Magnetization reversal in NiFe/IrMn exchange-biased thin films was investigated under thermal cycling in an external magnetic field, applied opposite to the direction of the exchange bias field. Thermal hysteresis of magnetization accompanied by changes in magnetization polarity was observed in the applied field close to the exchange bias value. This effect appears when thermally induced variations of the exchange bias exceed the corresponding variations in coercivity. The amplitude of magnetization reversal in NiFe/IrMn structures exceeds ~ 100 times the corresponding amplitude in spin-crossover molecular compounds. The observed bistability of the magnetic state, revealed by thermal hysteresis, gradually disappears with an increase in the number of cooling-heating thermal cycles, that indicates an irreversible quenching of the interfacial magnetization configuration. This effect paves the way for the creation of a new class of switching devices with thermally assisted bistability in the ferromagnetic state.

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Influence of seed layer on the magnetoresistance properties in IrMn-based magnetic tunnel junctions

Cited by 5 publications

References 43 publications

Engineering buffer layers to improve temperature resilience of magnetic tunnel junction sensors

Engineering buffer layers to improve temperature resilience of magnetic tunnel junction sensors

Surface Roughness-Induced Changes in Important Physical Features of CoFeSm Thin Films on Glass Substrates during Annealing

Thermal hysteresis of magnetization in NiFe/IrMn exchange-biased ferromagnet

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