Increase of temperature due to Joule heating during current-induced magnetization switching of an MgO-based magnetic tunnel junction

Lee, D. H.; Lim, Sang Ho

doi:10.1063/1.2943151

Cited by 51 publications

(33 citation statements)

References 14 publications

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“…By solving the heat diffusion equations in similar geometries, heating efficiencies of 15 1.4 and 10 5 KmW −1 .µm 2 were predicted and seem to corroborate our finding.…”

Section: Discussionsupporting

confidence: 76%

Spin-wave thermal population as temperature probe in magnetic tunnel junctions

Goff

Nikitin²,

Devolder

2016

Journal of Applied Physics

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We study whether a direct measurement of the absolute temperature of a Magnetic Tunnel Junction (MTJ) can be performed using the high frequency electrical noise that it delivers under a finite voltage bias. Our method includes quasi-static hysteresis loop measurements of the MTJ, together with the field-dependence of its spin wave noise spectra. We rely on an analytical modeling of the spectra by assuming independent fluctuations of the different sub-systems of the tunnel junction that are described as macrospin fluctuators. We illustrate our method on perpendicularly magnetized MgO-based MTJs patterned in 50 × 100 nm 2 nanopillars. We apply hard axis (in-plane) fields to let the magnetic thermal fluctuations yield finite conductance fluctuations of the MTJ. Instead of the free layer fluctuations that are observed to be affected by both spin-torque and temperature, we use the magnetization fluctuations of the sole reference layers. Their much stronger anisotropy and their much heavier damping render them essentially immune to spin-torque. We illustrate our method by determining current-induced heating of the perpendicularly magnetized tunnel junction at voltages similar to those used in spin-torque memory applications. The absolute temperature can be deduced with a precision of ±60 K and we can exclude any substantial heating at the spin-torque switching voltage.

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“…By solving the heat diffusion equations in similar geometries, heating efficiencies of 15 1.4 and 10 5 KmW −1 .µm 2 were predicted and seem to corroborate our finding.…”

Section: Discussionsupporting

confidence: 76%

Spin-wave thermal population as temperature probe in magnetic tunnel junctions

Goff

Nikitin²,

Devolder

2016

Journal of Applied Physics

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“…[29][30][31] Three scenarios are usually suggested to account for this phenomenon: process-induced damages, 15,32 current-induced heating, 33,34 or a nonlinear change of the frequency with high mode amplitude. 35 As we work with low bias current, current induced heating can be excluded in our case.…”

Section: A Materials and Geometry Parametersmentioning

confidence: 99%

Quantized spin-wave modes in magnetic tunnel junction nanopillars

et al. 2010

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We present an experimental and theoretical study of the magnetic field dependence of the mode frequency of thermally excited spin waves in rectangular shaped nanopillars of lateral sizes 60 × 100, 75 × 150, and 105 × 190 nm 2 , patterned from MgO-based magnetic tunnel junctions. The spin wave frequencies were measured using spectrally resolved electrical noise measurements. In all spectra, several independent quantized spin wave modes have been observed and could be identified as eigenexcitations of the free layer and of the synthetic antiferromagnet of the junction. Using a theoretical approach based on the diagonalization of the dynamical matrix of a system of three coupled, spatially confined magnetic layers, we have modeled the spectra for the smallest pillar and have extracted its material parameters. The magnetization and exchange stiffness constant of the CoFeB free layer are thereby found to be substantially reduced compared to the corresponding thin film values. Moreover, we could infer that the pinning of the magnetization at the lateral boundaries must be weak. Finally, the interlayer dipolar coupling between the free layer and the synthetic antiferromagnet causes mode anticrossings with gap openings up to 2 GHz. At low fields and in the larger pillars, there is clear evidence for strong non-uniformities of the layer magnetizations. In particular, at zero field the lowest mode is not the fundamental mode, but a mode most likely localized near the layer edges.

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“…STT may also assist the magnetization switching in nanopillar geometries [4,5], and it can increase the magnetization thermal noise [6], degrading the device performances. In nanopillar geometries, the magnetization dynamics takes place in a very confined region where the temperature is almost uniform [7], such that the temperature dynamics could be understood from simple experiments [5]. In contrast, the temperature rise and its spatial profile remain almost [8] unexplored in nanocontact (NC) devices.…”

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confidence: 99%

Understanding Nanoscale Temperature Gradients in Magnetic Nanocontacts

et al. 2012

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We determine the temperature profile in magnetic nanocontacts submitted to the very large current densities that are commonly used for spin-torque oscillator behavior. Experimentally, the quadratic current-induced increase of the resistance through Joule heating is independent of the applied temperature from 6 K to 300 K. The modeling of the experimental rate of the current-induced nucleation of a vortex under the nanocontact, assuming a thermally-activated process, is consistent with a local temperature increase between 150 K and 220 K. Simulations of heat generation and diffusion for the actual tridimensional geometry were conducted. They indicate a temperatureindependent efficiency of the heat sinking from the electrodes, combined with a localized heating source arising from a nanocontact resistance that is also essentially temperature-independent. For practical currents, we conclude that the local increase of temperature is typically 160 K and it extends 450 nm about the nanocontact. Our findings imply that taking into account the currentinduced heating at the nanoscale is essential for the understanding of magnetization dynamics in nanocontact systems.

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Increase of temperature due to Joule heating during current-induced magnetization switching of an MgO-based magnetic tunnel junction

Cited by 51 publications

References 14 publications

Spin-wave thermal population as temperature probe in magnetic tunnel junctions

Spin-wave thermal population as temperature probe in magnetic tunnel junctions

Quantized spin-wave modes in magnetic tunnel junction nanopillars

Understanding Nanoscale Temperature Gradients in Magnetic Nanocontacts

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