Helicity control in magnetic nanotubes

Tailoring dual reversal modes by helicity control in ferromagnetic nanotubes.
H. D. Salinas, J. Restrepo, and Òscar Iglesias

Phys. Rev. B 101, 054419 (2020)

Magnetic configurations along the hysteresis loops for the different reversal modes displayed in Fig. 4 (left and right columns correspond to panels (a) and (c) of that figure). Upper panels represent the height profiles of the quantities ⟨θ⟩, ⟨mz⟩, and <mϕ⟩  averaged per layer for the tube (8,15) and γ= 0.035, whereas lower ones present snapshots of the spin configurations taken at points labeled in Fig. 4.

Hopfions and all that in magnets

Skyrmion Knots in Frustrated Magnets
Paul SutcliffePhys. Rev. Lett. 118, 247203 (2017)

Static Hopf Solitons and Knotted Emergent Fields in Solid-State Noncentrosymmetric

Magnetic Nanostructures.

Jung-Shen B. Tai and Ivan I. Smalyukh

Phys. Rev. Lett. 121, 187201 (2018)

Binding a hopfion in a chiral magnet nanodisk.

Yizhou Liu, Roger K. Lake, and Jiadong Zang

Phys. Rev. B 98, 174437 (2018)

Advances in artificial spin ice: Review

Advances in artificial spin ice.
Sandra H. Skjærvø, Christopher H. Marrows, Robert L. Stamps & Laura J. Heyderman
Nature Reviews Physics (2019)

Discoveries will be driven by inspiration for new designs. The new designs will require the development of methods to manufacture them and to measure their dynamics. In this way, it will be possible to identify, characterize and control the emergent phenomena that will lead to new functionality in artificial spin ice. 

Van der Waals engineering of magnetism

Van der Waals engineering of magnetism

Ji-Hui Yang, Hongjun Xiang

Nature Materials 18, 1273 (2019)

a, Top and side view of monoclinic stacking with the antiferromagnetic interlayer coupling under zero pressure P. The green (purple) atoms represent the Cr atoms in the top (bottom) layer, and the brown ones represent the I atoms. Black arrows represent the spin direction. b, Same for rhombohedral stacking with the ferromagnetic interlayer coupling under a certain pressure, represented by the red arrows. hBN, hexagonal boron nitride.

Exchange-bias feature in core-shell nanoparticles

On the first evidence of exchange-bias feature in magnetically contrasted consolidates made from CoFe 2 O 4 -CoO core-shell nanoparticles.
Nancy Flores-Martinez, Giulia Franceschin, Thomas Gaudisson, Sonia Haj-Khlifa, Sarra Gam Derouich, Nader Yaacoub, Jean-Marc Grenèche, Nicolas Menguy, Raul Valenzuela & Souad Ammar
Scientific Reports 9, 19468 (2019)

Thermal variation of the saturation and remanent magnetizations (a) and that of the coercive and exchange magnetic fields (b) of CFO-CO ceramic, as inferred from its FC hysteresis loops (cooling field of 7 T) recorded at different temperatures.

Ferromagnetic excess moments and apparent exchange bias in FeF 2

Ferromagnetic excess moments and apparent exchange bias in FeF2 single crystals 
D. C. Joshi, P. Nordblad, R. Mathieu
Scientific Reports 9, 18884 (2019)

Temperature dependence of (a) magnetization M under FC in a magnetic field of H = 5 Oe, and (b) thermo-remnant magnetization (TRM) measured along perpendicular (⊥c), 45° and parallel to c-axis (||c) of the FeF2 circular disc. The inset shows a photograph of the top view (along the c-axis) of the FeF2 single crystal used in experiment.

Spin Waves Revealed with X-Ray Vision

Spin Waves Revealed with X-Ray Vision
Christopher Crockett
Physics - Synopsis

Direct observation of coherent magnons with suboptical wavelengths in a single-crystalline ferrimagnetic insulator

J. Förster, J. Gräfe, J. Bailey, S. Finizio, N. Träger, F. Groß, S. Mayr, H. Stoll, C. Dubs, O. Surzhenko, N. Liebing, G. Woltersdorf, J. Raabe, M. Weigand, G. Schütz, and S. Wintz

Phys. Rev. B 100, 214416 (2019)

Schematics of the sample architecture and measurement setup. (a) Direct x-ray intensity image of the sample's transmission window. The central dark horizontal stripe is the antenna. (b) Single time frame of the time-resolved measurement with dynamical normalization that emphasizes the spin waves over the static background. Grayscale values represent the changes of the out-of-plane magnetization component. (c) Result of time-domain Fourier analysis, showing amplitude and phase of the waves in HSV (hue-saturation-value) color space (color code above the image).

The Heat in Antiferromagnetic Switching

The Heat in Antiferromagnetic Switching
Barry Zink
Physics 12, 134 (2019)

Absence of Evidence of Electrical Switching of the Antiferromagnetic Néel Vector
C. C. Chiang, S. Y. Huang, D. Qu, P. H. Wu, and C. L. Chien
Phys. Rev. Lett. 123, 227203 (2019)

Schematics of the eight-terminal patterned structure with the pulsed writing current along the 45° (write 1) and the 135° (write 2) lines for (a) planar Hall and (b) longitudinal resistance measurements. Relative changes of Hall resistance in (c) Pt/NiO/Si and (e) Pt/NiO/glass and relative change of longitudinal resistance in (d) Pt/NiO/Si and (f) Pt/NiO/glass, after applying 10-ms writing current pulses alternately along the 45° and the 135° lines.

(Left) Platinum (Pt) strips grown on antiferromagnetic nickel oxide (NiO) films convert charge current to spin current, which is intended to switch the pointing direction of the insulating NiO’s spins. The switching is observed via a sawtooth voltage pattern. However, the Pt heats dramatically when the current is applied and (right) this heating reproduces the sawtooth pattern even when no antiferromagnet is present. 

Microtubes with radial magnetization

Magnetization reversal and local switching fields of ferromagnetic Co/Pd microtubes with radial magnetization
Norbert Puwenberg, Christopher F. Reiche, Robert Streubel, Mishal Khan, Dipankar Mukherjee, Ivan V. Soldatov, Michael Melzer, Oliver G. Schmidt, Bernd Büchner, Thomas Mühl

Phys. Rev. B 99, 094438 (2019)

Sketch of the extreme case where the MFM tip oscillates parallel to the local microtube surface (ϕ=90∘) with two different simplified magnetic domain configurations. (a) For domain walls parallel to the tip oscillation direction, no MFM signal is expected due to vanishing magnetostatic force z-component. (b) Domain walls perpendicular to the tip oscillation direction cause a detectable MFM signal.

Standardisation of magnetic NPs

Standardisation of magnetic nanoparticles in liquid suspension.

James Wells, Olga Kazakova, Oliver Posth, Uwe Steinhoff, Sarunas Petronis, Lara K Bogart, Paul Southern, Quentin Pankhurst and Christer Johansson

J. Appl. Phys. D 50, 383003 (2017)

Results of the NanoMag European FP7 project that aims to standardize, improve and redefine analysis methods for magnetic nanoparticles.

The 2017 Magnetism Roadmap

The 2017 Magnetism Roadmap
Several authors
J. Appl. Phys. D 50, 363001 (2017)

An update of the previously publish Magnetism Roadmap in 2014, now covering the following topics written by experts in the respective fields:
1. Atomic scale confinement effects in spin textures
2. Two-dimensional materials
3. Novel magnetic materials with curved geometries
4. Skyrmions and topological defects in magnetic materials
5. First-order magnetic phase transitions and nanoscale phase coexistence
6. Advances in magnetic characterization
7. Magneto-optics
8. Magneto-plasmonics
9. Ultrafast magnetisation dynamics (toward ultrafast spintronics)
10. Magnonic transport
11. Non-volatile memory and information storage
12. Antiferromagnetic spintronics
13. Magnets for energy applications
14. Magnetophoretic technology

Drug releasing nanoplatforms activated by alternating magnetic fields: Review

Drug releasing nanoplatforms activated by alternating magnetic fields.
Damien Mertz, Olivier Sandre, Sylvie Bégin-Colin
Biochimica et Biophysica Acta 1861, 1617 (2017)

Techniques in micromagnetic simulation and analysis

Techniques in micromagnetic simulation and analysis.
D Kumar and A O Adeyeye

J. Phys. D 50, 343001 (2017)

Tuning EB by control of interface coupling

Tuning the coercivity and exchange bias by controlling the interface coupling in bimagnetic core/shell nanoparticles.
Gabriel C. Lavorato, Enio Lima, Jr., Horacio E. Troiani, Roberto D. Zysler and Elin L. Winkler
Nanoscale 9, 10240 (2017)

Magneto-thermal capabilities of NP Review

Recent advances of magneto-thermal capabilities of nanoparticles: From design principles to biomedical applications.

Seung-hyun Noh, Seung Ho Moon, Tae-Hyun Shin, Yongjun Lim, Jinwoo Cheon
Nano Today 13, 61 (2017)

Direct Observation of Interactions between Nanoparticles and Nanoparticle Self-Assembly in Solution

Direct Observation of Interactions between Nanoparticles and Nanoparticle Self-Assembly in Solution.
Shu Fen Tan, See Wee Chee, Guanhua Lin, and Utkur MirsaidovAcc. Chem. Res., 50, 1303 (2017)

Influence of atomic lattice order on crystallinity of NP and their properties when a assembled

Impact of the Metallic Crystalline Structure on the Properties of Nanocrystals and Their Mesoscopic Assemblies.
Marie-Paule Pileni
Accounts of Chemical Research ASAP (2017)

The relation between structural atomic lattice and the degree of crystallinity of NP is nicely demonstrated here. Moreover, properties (mechanical, growth processes) of supracrystals also change with the nanocrystallinity of the nanoparticles used as building blocks.

Surface spin canting probed by EELS

Surface spin canting in Fe3O4 and CoFe2O4 NP probed by high-resolution electron energy loss spectroscopy.

D. S. Negi, H. Sharona, U. Bhat, S. Palchoudhury, A. Gupta, and R. Datta
Phys. Rev. B 95, 174444 (2017)

Experimental L3 spectra of CFO recorded (a) and (c) at room temperature and (b) and (d) at liquid nitrogen temperature (77 K) for Fe and Co atoms, respectively. The spectra from core and edge of nanoparticles are colored with green and red, respectively. Dominating features from Td and Oh atomic sites are marked. Kindly note the fine features are only sharper for Co atoms, but not for Fe atoms, suggesting possible formation of uniformly oriented spin canting configuration for Fe atoms but core-shell morphology for Co atoms.

Rev. Mod. Phys. 89, 025006 (2017) - Interface-induced phenomena in magnetism

Interface-induced phenomena in magnetism.
Frances Hellman et al.Rev. Mod. Phys. 89, 025006 (2017)

Spins in 3D with X Rays

Three-dimensional magnetization structures revealed with X-ray vector nanotomography.Claire Donnelly, Manuel Guizar-Sicairos, Valerio Scagnoli, Sebastian Gliga, Mirko Holler, Jörg Raabe & Laura J. Heyderman

Nature 547, 328 (2017)

Imaging techniques: X-rays used to watch spins in 3D.
Peter Fischer

Nature 547, 290–291 (2017)

Temperature-Induced Increase of Spin Spiral Periods

Temperature-Induced Increase of Spin Spiral Periods.
Aurore Finco, Levente Rózsa, Pin-Jui Hsu, André Kubetzka, Elena Vedmedenko, Kirsten von Bergmann, and Roland Wiesendanger
Phys. Rev. Lett. 119, 037202 (2017)

Relativistic Zitterbewegung in magnons

Magnonic analog of relativistic Zitterbewegung in an antiferromagnetic spin chain.
Weiwei Wang, Chenjie Gu, Yan Zhou, and Hans Fangohr
Phys. Rev. B 96, 024430 (2017)

(a) A positive wave packet and a negative packet that both have positive wave vector move in different directions. The amplitude $\left|\psi \right|$ is used for plotting. (b) Two positive wave packets with different wave vectors move toward each other too. (c) The normalized average position $⟨\xi ⟩$ as a function of time for the two cases.

Relativistic theory of magnetic inertia in ultrafast spin dynamics

Relativistic theory of magnetic inertia in ultrafast spin dynamics.
Ritwik Mondal, Marco Berritta, Ashis K. Nandy, and Peter M. Oppeneer
Phys. Rev. B 96, 024425 (2017)

Schematic illustration of magnetization dynamics. The precessional motion of M around Heff

 is depicted by the blue solid-dashed curve, and the nutation is shown by the red curve.

Magnetic Möbius stripe

Magnetic Möbius stripe without frustration: Noncollinear metastable states.
S. Castillo-Sepúlveda, R. A. Escobar, D. Altbir, M. Krizanac, and E. Y. Vedmedenko
Phys. Rev. B 96, 024426 (2017)

Equilibrium MC configuration of a chain consisting of 100 moments for $D=1,K=0.4$ meV, $J=-40$ meV: (a) closed KB configuration and (b) the same shown with open ends for clarity.

Vortices in ferromagnetic nanotubes

Imaging magnetic vortex configurations in ferromagnetic nanotubes.
M. Wyss, A. Mehlin, B. Gross, A. Buchter, A. Farhan, M. Buzzi, A. Kleibert, G. Tütüncüoglu, F. Heimbach, A. Fontcuberta i Morral, D. Grundler, and M. Poggio
Phys. Rev. B 96, 024423 (2017)

XMCD-PEEM images of a 6.9-$\mu m$-long Py NT with (a) $\hat{k}\perp \hat{n}$ and (b) $\hat{k}\parallel \hat{n}$ and of a 7.2-$\mu m$-long CoFeB NT with (c) $\hat{k}\perp \hat{n}$ and (d) $\hat{k}\parallel \hat{n}$. Dashed outlines indicate the positions of the NTs. Panels (e–h) represent 2-$\mu m$-long $I_{\text{XMCD}}$linecuts along the corresponding colored dashed lines in (a–d). In the linecuts, the background intensity is indicated by the level of the horizontal dashed lines and vertical dashed lines delineate the boundaries of the NT. Panels (i) and (j) show simulated remnant magnetic states for a NT with $l=2.1\mu m$ and $d=245$ nm. Both configurations are mixed states with an axial central domain and vortex ends of either (i) opposing circulation—consistent with (a) and (b)—or (j) matching circulation—consistent with (c) and (d). The color scale corresponds to normalized magnetization along $\hat{y}$. Arrowheads indicate the local magnetization direction.