Domain-Wall Induced Large Magnetoresistance Effects at Zero Applied Field in Ballistic Nanocontacts

Bieren, Arndt von; Patra, Ajit Kumar; Krzyk, Stephen; Rhensius, Jan; Reeve, Robert M.; Heyderman, Laura J.; Hoffmann‐Vogel, Regina; Kläui, Mathias

doi:10.1103/physrevlett.110.067203

Cited by 16 publications

(20 citation statements)

References 31 publications

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“…From the structural properties of the electromigration process observed here and the large holes that appear, it is clear that tunneling is not expected at the initial and intermediate electromigration stages, because the holes are much too large to allow tunneling. This is in agreement with observations for permalloy that tunneling is not observed and also the dR=dU characteristics do not show non-linearities even at rather high resistance values (von Bieren et al, 2013).…”

Section: B Structural Evolution During Electromigration Of Alloyssupporting

confidence: 93%

Electromigration and the structure of metallic nanocontacts

Hoffmann‐Vogel

2017

Applied Physics Reviews

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FIG. 5. STM set-up used in the literature for studying nanoscale metallic junctions with TEM. The set-up very much resembles a standard STM setup, except that this instrument is used under the electron beam of a TEM. Reprinted with permission from Ohnishi et al., Nature 395, 780 (1998). FIG. 6. (a) If microscopic and macroscopic effects are to be summarized in one picture, diffusion under the influence of electromigration forces can be understood as hopping in a tilted washboard-potential. (b) Energy landscape for a hopping atom with a definition of its energy parameters.

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Section: B Structural Evolution During Electromigration Of Alloyssupporting

confidence: 93%

Electromigration and the structure of metallic nanocontacts

Hoffmann‐Vogel

2017

Applied Physics Reviews

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“…In our case we find that in general the AMR contribution from the DW increases for smaller constrictions. However the size of the AMR contribution is rather small, on the order of 1-2 %, in agreement with previous reports of AMR in Py nanocontacts [22,49], with sub 1 % changes for evolving contact size within the studied range, which is much smaller than the total effects we observe, and hence we now consider alternative explanations for the DWMR we observe.…”

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confidence: 93%

Scaling of intrinsic domain wall magnetoresistance with confinement in electromigrated nanocontacts

et al. 2019

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In this work we study the evolution of intrinsic domain wall magnetoresistance (DWMR) with domain wall confinement. Clean permalloy notched half-ring nanocontacts are fabricated using a special ultra-high vacuum electromigration procedure to tailor the size of the wire in-situ and through the resulting domain wall confinement we tailor the domain wall width from a few tens of nm down to a few nm. Through measurements of the dependence of the resistance with respect to the applied field direction we extract the contribution of a single domain wall to the MR of the device, as a function of the domain wall width in the confining potential at the notch. In this size range, an intrinsic positive MR is found, which dominates over anisotropic MR, as confirmed by comparison to micromagnetic simulations. Moreover, the MR is found to scale monotonically with the size of the domain wall, δ DW , as 1/δ b DW , with b = 2.31 ± 0.39. The experimental result is supported by quantum-mechanical transport simulations based on ab-initio density functional theory calculations.arXiv:1812.05689v1 [cond-mat.mes-hall]

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“…While in either state, the MR changes smoothly and reversibly with field, due to a coherent magnetization process under a field. To remove the contribution of the coherent magnetization process, we measure the DW-induced resistance by extracting the total resistance change (ΔR) and MR (ΔR/R 0 ) of the nanostructure between the single-DW state (with resistance R 0 + ΔR) and the single-domain state (with resistance R 0 ) at zero magnetic field [11,18,39]. At 5.0 K, the DW-induced ΔR is found to be 4.5 mΩ, and the associated ΔR/R 0 is 0.053%.…”

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confidence: 99%

Resistance of domain-wall states in half-metallic CrO2

2018

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The half-metallic CrO 2 with nearly 100% spin polarization is an ideal system to study magnetic domain wall resistance, which differs from the resistance (or resistivity) inside a single-domain. To experimentally measure the domain wall resistance, we design and prepare a special CrO 2 epitaxial nanostructure with an asymmetrical weak link to localize a single domain wall, by using the techniques of chemical vapor deposition and selective-area growth. This structure provides a capability to generate and annihilate a domain wall near the weak link. By contrasting the resistance between a single-domain state and a domain state, we observe a repeatable and reversible resistance jump, namely domain wall resistance, in half metallic CrO 2. Using the Levy-Zhang model, we further obtain the spin asymmetry ratio / between resistivities in the two spin channels. The ratio, 4256 ± 388 at 5.0 K, is much larger than that of conventional ferromagnetic metals, attesting the half-metallicity of CrO 2 .

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Domain-Wall Induced Large Magnetoresistance Effects at Zero Applied Field in Ballistic Nanocontacts

Cited by 16 publications

References 31 publications

Electromigration and the structure of metallic nanocontacts

Electromigration and the structure of metallic nanocontacts

Scaling of intrinsic domain wall magnetoresistance with confinement in electromigrated nanocontacts

Resistance of domain-wall states in half-metallic CrO2

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