β-Mn-Type Co8+xZn12–x as a Defect Cubic Laves Phase: Site Preferences, Magnetism, and Electronic Structure

Xie, Weiwei; Thimmaiah, Srinivasa; Lamsal, Jagat; Liu, Jing; Heitmann, Thomas; Quirinale, D. G.; Goldman, A. I.; Pecharsky, V. K.; Miller, Gordon J.

doi:10.1021/ic4009653

Cited by 38 publications

(41 citation statements)

References 53 publications

(78 reference statements)

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“…We thus conclude that in Co 8 Zn 8 Mn 3 Fe the Fe ion entirely occupies the 12d-sites, together with Mn and Zn, while Co occupies the 8c-site. Comparing our fit result with previous reports (see [13]), we find good agreement regarding atomic coordinates. The rather large B iso values of the 12d sites suggest some strain disorder on this site, likely as result of the doping [19].…”

Section: Neutron Diffractionsupporting

confidence: 89%

“…Polycrystalline samples of the pseudoternary compound Co 8 Zn 8 Mn 4−x Fe x with x=0, 0.2, 0.35, 0.5, and 1 as well as a Co 8 Zn 9 Mn 3 specimen were synthesized by a thermal reaction similar as described in [13]. Stoichiometric amounts of Co (Chempur, 99.95%), Zn (Koch, 99.999 8%), Mn (Chempur, 99.99%), and Fe (Alfa Aesar, 99.98%) were sealed in an evacuated quartz tube (p<10 −5 mbar), heated to 1100°C for 12 hours and cooled down to 925°C with a cooling rate of 1K h −1 .…”

Section: Sample Preparationmentioning

confidence: 99%

“…In bulk material, skyrmions are stabilized by the Dzyaloshinskii-Moriya-interaction, which (in a picture of local moments) for neighboring spins S i , S j produces an exchange term H∝S i ×S j not equal to zero for non- Suggested by [13], for Co 8 Zn 8 Mn 4 we expect Co to occupy the 8c sites, while Zn and Mn sit on the 12d sites. For Fe doping, conceptually, in the present case, three scenarios appear possible, that is Fe exclusively occupies either the 12d or 8c sites (i.e.…”

Section: Neutron Diffractionmentioning

confidence: 99%

“…With their similar atomic numbers, for the 3d transition metals Co, Zn, Mn and Fe a determination of the elemental site occupation by means of x-ray powder diffraction is not attainable. Instead, as has been demonstrated in the [13,18], neutron powder diffraction provides a much brighter elemental contrast and thus allows to determine the elemental occupation of the distinct crystallographic sites. Therefore, we have carried out a neutron scattering investigation using the Fine Resolution Powder Diffractometer E9 of the BENSC, Helmholtz-Center Berlin, to structurally characterize two materials out of the series Co 8 Experiments have been carried out in zero field, with one run each for a temperature above/below T C , that is at 300 and 440 K. A neutron wavelength of λ=1.7982 Åhas been used.…”

Section: Neutron Diffractionmentioning

confidence: 99%

“…After all, the class of materials stems from Co 8 Zn 12 , where Co and Zn occupy crystallographic nonequivalent sites. In a neutron-powder-diffraction study of the compound Co 10 Zn 10 it has been demonstrated that there is a preferential occupation for the two Wyckhoff positions, with Cobalt on the 8c-sites, and a Zn/Co mixture on the 12d-sites [13]. In doping experiments such as on Co 8−x Fe x Zn 8 Mn 4 or Co 8 Zn 8 Mn 4−x Fe x it is thus of interest to study if the preferential site occupation is retained by the Fe atom, and if it affects relevant magnetic properties.…”

Section: Introductionmentioning

confidence: 99%

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Local structure determination in helimagnetic ${\mathrm{Co}}_{8}{\mathrm{Zn}}_{8}{\mathrm{Mn}}_{4-x}{\mathrm{Fe}}_{x}$

et al. 2019

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We have carried out a structural and magnetic characterization of Co 8 Zn 8+y Mn 4−y−x Fe x by means of bulk techniques, powder neutron scattering and Mössbauer spectroscopy. From our data, we derive the main magnetic parameters and carry out a detailed structural characterization. We observe that disorder is present in our samples in various forms and that this seems to be generic for this class of materials. However, the disorder appears to have little impact on the character of the magnetic phases, and thus seems to be of no relevance for the skyrmionic phases established for these types of materials.

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Section: Neutron Diffractionsupporting

confidence: 89%

Section: Sample Preparationmentioning

confidence: 99%

Section: Neutron Diffractionmentioning

confidence: 99%

Section: Neutron Diffractionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Local structure determination in helimagnetic ${\mathrm{Co}}_{8}{\mathrm{Zn}}_{8}{\mathrm{Mn}}_{4-x}{\mathrm{Fe}}_{x}$

et al. 2019

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Noncentrosymmetric Magnets Hosting Magnetic Skyrmions

2017

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with n = m/|m| being an unit vector parallel to the local magnetic moment m. [10,11] This means that the arrangement of spins within a single skyrmion can wrap a sphere nonzero integer times. The case of Φ = ± 1 is exemplified in Figure 1a, which suggests the topologically protected nature of the skyrmion spin texture.To stabilize such magnetic skyrmions, several different approaches have been proposed. For example, the interplay between the magnetic dipole-dipole interaction and uniaxial magnetic anisotropy often leads to the formation of a cylindrical magnetic domain structure termed magnetic bubble, [15][16][17][18] which is known to host various integer skyrmion numbers in cases depending on the detail of the internal spin texture. [19][20][21] The magnetic bubble was once utilized as the information carrier for magnetic storage devices (i.e., magnetic bubble memory), which was commercially available in the 1980s but later discontinued partly because the relatively large size of the magnetic bubble (≈1 μm) prevents further improvement of information density. Some latest studies suggest the possible miniaturization of bubble size down to sub-micron scale in multi-layered thin films with finely tuned magnetic parameters. [22,23] More recently, the experimental discovery of nanometric skyrmions has been reported for a series of ferromagnets with noncentrosymmetric crystal structure, where antisymmetric exchange interaction, i.e. Dzyaloshinskii-Moriya (DM) interaction, [24,25] originating from relativistic spin-orbit interaction plays a key role for the skyrmion formation. In this case, the size of skyrmion or the associated magnetic modulation period λ is determined by the ratio between the magnitudes of DM interaction D and ferromagnetic exchange interaction J in form of λ ∝ J/D, which typically ranges from 1 to 100 nm. The internal spin texture of magnetic skyrmions essentially depends on the symmetry of the underlying crystallographic lattice and associated DM interaction. [8,26] So far, most of the single-component materials showing magnetic skyrmions possess a chiral crystal structure, where Bloch-type skyrmions with a vortex-like swirling spin texture (Figure 1b) are observed. [10,12,[27][28][29][30] In contrast, under the uniaxial polar crystal structure, [31] the emergence of Néel type skyrmion with radial spin texture (Figure 1c) has been proposed. [8,26,32] Bloch (Néel) type skyrmions can form close-packed 2D hexagonal lattice (Figure 1f), which can be viewed as the superposition The concept of a skyrmion, which was first introduced by Tony Skyrme in the field of particle physics, has become widespread in condensed matter physics to describe various topological orders. Skyrmions in magnetic materials have recently received particular attention; they represent vortex-like spin structures with the character of nanometric particles and produce fascinating physical properties rooted in their topological nature. Here, a series of noncentrosymmetric ferromagnets hosting skyrmions is reviewed: B20 metals, Cu...

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Current‐Induced Nucleation and Annihilation of Magnetic Skyrmions at Room Temperature in a Chiral Magnet

Morikawa

Tokunaga

et al. 2017

Advanced Materials

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A magnetic skyrmion is a nanometer-scale magnetic vortex carrying an integer topological charge. Skyrmions show a promise for potential application in low-power-consumption and high-density memory devices. To promote their use in applications, it is attempted to control the existence of skyrmions using low electric currents at room temperature (RT). This study presents real-space observations for the current-induced formation and annihilation of a skyrmion lattice (SkL) as well as isolated skyrmions in a microdevice composed of a thin chiral magnet Co Zn Mn with a Curie temperature, T ≈ 325 K, above RT. It is found that the critical current for the manipulation of Bloch-type skyrmions is on the order of 10 A m , approximately three orders of magnitude lower than that needed for the creation and drive of ferromagnetic (FM) domain walls in thin FM films. The in situ real-space imaging also demonstrates the dynamical topological transition from a helical or conical structure to a SkL induced by the flow of DC current, thus paving the way for the electrical control of magnetic skyrmions.

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β-Mn-Type Co_8+xZn_12–x as a Defect Cubic Laves Phase: Site Preferences, Magnetism, and Electronic Structure

Cited by 38 publications

References 53 publications

Local structure determination in helimagnetic ${\mathrm{Co}}_{8}{\mathrm{Zn}}_{8}{\mathrm{Mn}}_{4-x}{\mathrm{Fe}}_{x}$

Local structure determination in helimagnetic ${\mathrm{Co}}_{8}{\mathrm{Zn}}_{8}{\mathrm{Mn}}_{4-x}{\mathrm{Fe}}_{x}$

Noncentrosymmetric Magnets Hosting Magnetic Skyrmions

Current‐Induced Nucleation and Annihilation of Magnetic Skyrmions at Room Temperature in a Chiral Magnet

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