Reduced-dimensionality-induced helimagnetism in iron nanoislands

Phark, Soo-hyon; Fischer, Jeison A.; Corbetta, Marco; Sander, Dirk; Nakamura, Kohji; Kirschner, J.

doi:10.1038/ncomms6183

Cited by 28 publications

(41 citation statements)

References 34 publications

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“…Not only the sign of the asymmetry is preserved, but also the monotonous variation as a function of θ Co . The physical concept reported here can be of general application in a large variety of magnetic substrates with noncollinear ground states: 2 AL Fe/Cu(111) [26], 2 AL Mn/W(110) [22], 1 AL Mn/W(100) [27], 1 AL Mn/Ag(111) [21], 2 AL Fe/W(110) [28], 1 AL Fe/Ir(111) [29], and NiMn(001) [30]. This work opens a way to study not only the coupling of adatoms to those substrates, but also the possible magnetic interactions among atoms in artificial structures built by atomic manipulation.…”

Section: (D) and 2(e) Provided That P T = 0 And Aφ/w < 90mentioning

confidence: 99%

Spin-sensitive shape asymmetry of adatoms on noncollinear magnetic substrates

et al. 2016

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The spin-resolved density of states of Co atoms on a noncollinear magnetic support displays a distinct shape contrast, which is superimposed on the regular height contrast in spin-polarized scanning tunneling microscopy. The apparent atom height follows the well-known cosine dependence on the angle formed by the tip and adatom local magnetization directions, whereas the shape contrast exhibits a sine dependence. We explain this effect in terms of a noncollinear spin density induced by the substrate, which in our case is the spin spiral of the Mn monolayer on W(110). The two independent contrast channels, apparent height and shape, are identified with the Co magnetization projections onto two orthogonal axes. As a result, all components of the overall atom magnetic moment vector can be determined with a single spin-sensitive tip in the absence of an external magnetic field. This result should be general for any atom deposited on noncollinear magnetic layers. DOI: 10.1103/PhysRevB.93.125424The control of the spin degree of freedom down to the single-atom limit is nowadays a central research issue [1][2][3][4][5][6][7], fostered by the increasing need for miniaturization and lowering power consumption in communication technologies. The most suitable technique to address the problem is spinpolarized scanning tunneling microscopy (SP-STM) [8], which has proven to be an excellent tool to perform single-atom magnetometry [1,6]. The design of magnetic structures with a given functionality calls for atomic-scale engineering by means of atomic manipulation or self-assembly of lowdimensional structures. Both of them can be combined with SP-STM [6,7,9,10]. For that reason, getting insight into the underlying physics of SP-STM and extending its range of applications is of crucial relevance. The SP-STM principle is the magneto-conductance effect in magnetic tunnel junctions [8,[11][12][13][14], and relies on probing the imbalance between majority and minority spins in the local density of states (LDOS) with respect to a particular magnetic quantization axis. Following the same notation as in Ref. [15], the spinpolarized tunneling current at sample bias V readswhere ρ T and P T are the tip's density of states and spin polarization,ρ s andm s the integrated sample total density of states and magnetization at r (tip position), and θ the angle formed between the tip and local sample magnetization. As a consequence, a SP-STM tip is only sensitive to the projection onto its magnetization direction, m s cos θ , and not to all other components ofm s . Here we show that the situation is radically different if the substrate's magnetic ground state is noncollinear within the spatial extent of an atomic wave function. Owing to the breaking of translational symmetry in spin space associated with the noncollinearity, the atoms' apparent shapes become distorted in spin-resolved STM images. We find that the strength of such distortion provides a quantitative measurement of the total spin component orthogonal to the default sensitivity direct...

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Section: (D) and 2(e) Provided That P T = 0 And Aφ/w < 90mentioning

confidence: 99%

Spin-sensitive shape asymmetry of adatoms on noncollinear magnetic substrates

et al. 2016

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“…Spin-polarized scanning tunneling microscopy and spectroscopy (spin-STM/S) is a magnetic imaging technique with an ultimate lateral resolution on the atomic scale [1–4], which is suitable for probing magnetism in ferromagnetic nanostructures [5–7] and in antiferromagnets [8–10]. Figure 1a schematically describes electron tunneling in spin-STM.…”

Section: Introductionmentioning

confidence: 99%

“…Here we focus on biatomic-layer-high (BLH) Co, Fe, and Fe-decorated Co (Fe|Co) islands on Cu(111) [7, 18–20]. Figure 2a schematically illustrates the sample preparation procedure.…”

Section: Introductionmentioning

confidence: 99%

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Spin-polarized scanning tunneling microscopy with quantitative insights into magnetic probes

Phark

Sander

2017

Nano Convergence

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Spin-polarized scanning tunneling microscopy and spectroscopy (spin-STM/S) have been successfully applied to magnetic characterizations of individual nanostructures. Spin-STM/S is often performed in magnetic fields of up to some Tesla, which may strongly influence the tip state. In spite of the pivotal role of the tip in spin-STM/S, the contribution of the tip to the differential conductance dI/dV signal in an external field has rarely been investigated in detail. In this review, an advanced analysis of spin-STM/S data measured on magnetic nanoislands, which relies on a quantitative magnetic characterization of tips, is discussed. Taking advantage of the uniaxial out-of-plane magnetic anisotropy of Co bilayer nanoisland on Cu(111), in-field spin-STM on this system has enabled a quantitative determination, and thereby, a categorization of the magnetic states of the tips. The resulting in-depth and conclusive analysis of magnetic characterization of the tip opens new venues for a clear-cut sub-nanometer scale spin ordering and spin-dependent electronic structure of the non-collinear magnetic state in bilayer high Fe nanoislands on Cu(111).

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“…In the case of 2 ML Fe islands on Cu(111), it has been shown that a martensitic phase transition between ferromagnetic body-centered cubic(bcc) and antiferromagnetic facecentered cubic (fcc) phases is induced upon application of high electric fields. Herein, the coexistence of two different crystallographic phases and the complex magnetic order are closely interwoven 3,6 . Considering the interatomic distances between nearest neighbors d nn and the resulting lattice mismatch, a Ni(111) surface where d nn = 248 pm should be an ideal candidate to promote the coexistence of Fe fcc (d nn = 253 pm) and bcc (d nn = 247 pm) films.…”

mentioning

confidence: 99%

Electric-field-induced switching from fcc to hcp stacking of a single layer of Fe/Ni(111)

2015

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We present a detailed study of an electric-field induced phase transition of a single layer of Fe on a Ni(111) substrate. Scanning tunneling microscopy at 4 K substrate temperature is used to provide the necessary electric field and to follow the transition from face-centered cubic to hexagonal closepacked stacking with atomic resolution.The concept of electric-field induced switching of magnetic metallic nanosystems is of particular interest in the view of potential applications in data storage devices and led to a tremendous increase of research activities during the last few years 1-5 . In the case of 2 ML Fe islands on Cu(111), it has been shown that a martensitic phase transition between ferromagnetic body-centered cubic(bcc) and antiferromagnetic facecentered cubic (fcc) phases is induced upon application of high electric fields. Herein, the coexistence of two different crystallographic phases and the complex magnetic order are closely interwoven 3,6 . Considering the interatomic distances between nearest neighbors d nn and the resulting lattice mismatch, a Ni (111)

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Reduced-dimensionality-induced helimagnetism in iron nanoislands

Cited by 28 publications

References 34 publications

Spin-sensitive shape asymmetry of adatoms on noncollinear magnetic substrates

Spin-sensitive shape asymmetry of adatoms on noncollinear magnetic substrates

Spin-polarized scanning tunneling microscopy with quantitative insights into magnetic probes

Electric-field-induced switching from fcc to hcp stacking of a single layer of Fe/Ni(111)

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