Stabilization of the easy-cone magnetic state in free layers of magnetic tunnel junctions

Teixeira, B. M. S.; Timopheev, A. A.; Caçoilo, N.; Auffret, S.; Sousa, R. C.; Diény, B.; Соболев, Н. А.

doi:10.1103/physrevb.100.184405

Cited by 13 publications

(12 citation statements)

References 37 publications

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“…We found a similar magnetization increase for Co. A second feature is the lowering in magnetization towards the W interface, which is more pronounced after 0.7 nm from the MgO interface (thickness of the two sublayers) . This decrease is ascribed to a localized reduction of M S and T C due to alloying of CoFeB with W , as proposed earlier [22]. This is supported by a 0.5 nm roughness at the CoFeB/W interface.…”

Section: Discussionsupporting

confidence: 81%

Depth-resolved magnetization profile of MgO/CoFeB/W perpendicular half magnetic tunnel junctions

et al. 2022

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In this work, we used the soft X-ray resonant magnetic reflectivity to study the depth-resolved out-of-plane ( oop) magnetization profile of a CoFeB/MgO sample with W/Ta cap layer after annealing at 400°C. It is a powerful technique to probe buried magnetic interfaces of ultra-thin films by combining the depth-resolved information of X-ray reflectivity with the species selectivity of X-ray magnetic circular dichroism. It allowed us to resolve the oop magnetization within a 1.36 nm thick CoFeB layer by the measurement of angle-dependent specular reflectivity at large scattering angles (up to 80°). We determined a graded magnetic distribution for both Fe and Co with a 20% increase at the interface with MgO, decreasing slightly over a thickness of 0.7 nm from MgO before it rapidly decreases to 50% at the interface with W. After applying a non-saturating magnetic field in the plane of the sample, we also quantified a similar magnetization profile with an inclined moment configuration. This indicates that the magnetization gradient is a robust property of the CoFeB layer in the studied sample.

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Section: Discussionsupporting

confidence: 81%

Depth-resolved magnetization profile of MgO/CoFeB/W perpendicular half magnetic tunnel junctions

et al. 2022

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“…, as pointed out in Ref. 31 . Thus, starting with the multilayer irradiated with 15 2 10 cm − , which exhibits a K1eff B0  (see figure 6(a)), i.e.…”

Section: Stack Properties After Irradiationmentioning

confidence: 65%

“…Refs. 30,31 ). However, ion irradiation has a known detrimental effect on the tunnel magnetoresistance (TMR), that has been reported for AlOx-based 2,32 and MgO-based 3,33 MTJs, usually attributed to the creation of defects within the oxide barrier.…”

Section: Introductionmentioning

confidence: 99%

Ar⁺ ion irradiation of magnetic tunnel junction multilayers: impact on the magnetic and electrical properties

Teixeira¹,

Timopheev²,

Caçoilo³

et al. 2020

J. Phys. D: Appl. Phys.

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The impact of 400 keV Ar + irradiation on the magnetic and electrical properties of in-plane magnetized magnetic tunnel junction (MTJ) stacks was investigated by ferromagnetic resonance, vibrating sample magnetometry and current-in-plane tunneling techniques. The ion fluences ranged from 12 2 10 cm − to 15 2 5×10 cm − . Below 14 2 1 0 cm − , the anisotropy of the Ta-capped FeCoB free layer was weakly modulated, following a decrease in the saturation magnetization. The tunnel magnetoresistance (TMR), along with the exchange bias and the interlayer exchange coupling providing a stable magnetic configuration to the reference layer, decreased continuously. Above 14 2 10 cm − , a strong decrease in the saturation magnetization was accompanied by a loss of the magnetic coupling and of the TMR. We show there is an ion-fluence window where the modulation of magnetic anisotropy can occur, while preserving a large TMR and stable magnetic configuration of the MTJ and demonstrate that the layers surrounding the free layer play a decisive role in determining the trend of the magnetic anisotropy modulation resulting from the irradiation. Our results provide guidance for the tailoring of MTJ parameters via ion irradiation, which we propose as a potentially suitable technique for setting the magnetic easy-cone state in MTJ for attaining fieldfree, fast and non-stochastic magnetization switching.

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“…Accordingly, the loss of perpendicular Magnetic Anisotropy was documented in CoPt multilayers over 10 15 Ga + ions/cm 2 irradiation in [30] and in [31]. In particular, the substitution of Ta, as the cap layer, with W seems to be beneficial to avoid deleterious material inter diffusion [32]. Thermal switching and temperature effects appearing to be a serious concern, one more important temperature-dependent processes should be analysed, since it could lead to the loss of the stored information.…”

Section: A H C Degradation and The Role Of Synthetic Antiferromagnetic Layermentioning

confidence: 97%

SEU Mechanisms in Spintronic Devices: Critical Parameters and Basic Effects

Coi

Adrianjohany²,

Pendina

et al. 2021

IEEE Trans. Nucl. Sci.

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The paper investigates radiation-induced switching mechanisms, temperature effects, breakdown voltage, sensitive volume and critical charge definitions for Spin-Transfer Torque Magnetic Tunnel Junction. Thermal spike model is adopted to estimate the temperature reached during heavy ion irradiation and temperature effects are suggested to be responsible for the magnetic properties degradation and for upset processes.

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Stabilization of the easy-cone magnetic state in free layers of magnetic tunnel junctions

Cited by 13 publications

References 37 publications

Depth-resolved magnetization profile of MgO/CoFeB/W perpendicular half magnetic tunnel junctions

Depth-resolved magnetization profile of MgO/CoFeB/W perpendicular half magnetic tunnel junctions

Ar⁺ ion irradiation of magnetic tunnel junction multilayers: impact on the magnetic and electrical properties

SEU Mechanisms in Spintronic Devices: Critical Parameters and Basic Effects

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Stabilization of the easy-cone magnetic state in free layers of magnetic tunnel junctions

Cited by 13 publications

References 37 publications

Depth-resolved magnetization profile of MgO/CoFeB/W perpendicular half magnetic tunnel junctions

Depth-resolved magnetization profile of MgO/CoFeB/W perpendicular half magnetic tunnel junctions

Ar+ ion irradiation of magnetic tunnel junction multilayers: impact on the magnetic and electrical properties

SEU Mechanisms in Spintronic Devices: Critical Parameters and Basic Effects

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Product

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Ar⁺ ion irradiation of magnetic tunnel junction multilayers: impact on the magnetic and electrical properties