Thursday, 7 September 2017

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.

Monday, 4 September 2017

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

Friday, 28 July 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.

Thursday, 27 July 2017

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.

Monday, 24 July 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

Friday, 21 July 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 |ψ| is used for plotting. (b) Two positive wave packets with different wave vectors move toward each other too. (c) The normalized average position ξ 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.

Tuesday, 18 July 2017

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-μm-long Py NT with (a) ˆkˆn and (b) ˆkˆn and of a 7.2-μm-long CoFeB NT with (c) ˆkˆn and (d) ˆkˆn. Dashed outlines indicate the positions of the NTs. Panels (e–h) represent 2-μm-long IXMCDlinecuts 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=2.1μm 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 ˆy. Arrowheads indicate the local magnetization direction.

Saturday, 15 July 2017

DMI across AFM-FM Interface

Dzyaloshinskii-Moriya Interaction across an Antiferromagnet-Ferromagnet Interface.
Xin Ma, Guoqiang Yu, Seyed A. Razavi, Stephen S. Sasaki, Xiang Li, Kai Hao, Sarah H. Tolbert, Kang L. Wang, and Xiaoqin Li
Phys. Rev. Lett. 119, 027202 (2017)
(a) Schematics of BLS experiment and possible atomic arrangement at the interface. (b) BLS spectra for DE spin waves recorded at a fixed incident angle with k=16.7rad/μm under oppositely oriented external magnetic fields H. The solid lines represent fittings with Lorentzian functions.

Wednesday, 12 July 2017

DW dynamics in synthetic antiferromagnets

Novel domain wall dynamics in synthetic antiferromagnets.
and J. Phys.: Condens. Matter 29, 303001 (2017)
Illustration of the ECT driven DW motion in SF (a) and SAF (b) wires in the presence of spin Hall torque and DMI field.

Wednesday, 5 July 2017

Magnetic skyrmions: Review of recent advances

Magnetic skyrmions: advances in physics and potential applications.
Albert Fert, Nicolas Reyren,Vincent Cros
Nature Reviews Materials 2, 17031 (2017)

Tuesday, 4 July 2017

Skyrmions in Noncentrosymmetric Magnets: Review

Noncentrosymmetric Magnets Hosting Magnetic Skyrmions.

Naoya Kanazawa, Shinichiro Seki, and Yoshinori Tokura
Advanced Materials 29, 1603227 (2017)

Monday, 3 July 2017

Equilibrium magnetization and magnetization relaxation of multicore magnetic nanoparticles

Equilibrium magnetization and magnetization relaxation of multicore magnetic nanoparticles.
Patrick Ilg
Phys. Rev. B 95, 214427 (2017)
Left: Visualization of a dense random cluster containing N=100 nanoparticles prepared as described in Sec. 3a. Right: Visualization of a cluster containing N=100 nanoparticles prepared by DLCA with Qdd=2 and ɛ=4 as described in Sec. 3b.

Friday, 30 June 2017

Surface design of magnetic nanoparticles for stimuli-responsive cancer imaging and therapy

Surface design of magnetic nanoparticles for stimuli-responsive cancer imaging and therapy
Taegyu Kang, Fangyuan Li, Seungmin Baik, Wei Shao, Daishun Ling, Taeghwan Hyeon
Biomaterials 136, 98 (2017)

Thermal Decomposition Synthesis of Iron Oxide Nanoparticles with Diminished Magnetic Dead Layer by Controlled Addition of Oxygen - ACS Nano (ACS Publications)

Thermal Decomposition Synthesis of Iron Oxide Nanoparticles with Diminished Magnetic Dead Layer by Controlled Addition of Oxygen.
Mythreyi Unni,Amanda M. Uhl, Shehaab Savliwala, Benjamin H. Savitzky, Rohan Dhavalikar, Nicolas Garraud, David P Arnold, Lena F. Kourkoutis, Jennifer S. Andrew, and Carlos Rinaldi
Decades of research focused on size and shape control of iron oxide nanoparticles have led to methods of synthesis that afford excellent control over physical size and shape but comparatively poor control over magnetic properties. Popular synthesis methods based on thermal decomposition of organometallic precursors in the absence of oxygen have yielded particles with mixed iron oxide phases, crystal defects, and poorer than expected magnetic properties, including the existence of a thick “magnetically dead layer” experimentally evidenced by a magnetic diameter significantly smaller than the physical diameter. Here, we show how single-crystalline iron oxide nanoparticles with few defects and similar physical and magetic diameter distributions can be obtained by introducing molecular oxygen as one of the reactive species in the thermal decomposition synthesis. This is achieved without the need for any postsynthesis oxidation or thermal annealing. These results address a significant challenge in the synthesis of nanoparticles with predictable magnetic properties and could lead to advances in applications of magnetic nanoparticles.

Standardizing Size- and Shape-Controlled Synthesis of Monodisperse Magnetite (Fe3O4) Nanocrystals by Identifying and Exploiting Effects of Organic Impurities

Standardizing Size- and Shape-Controlled Synthesis of Monodisperse Magnetite Nanocrystals by Identifying and Exploiting Effects of Organic Impurities.
Liang Qiao, Zheng Fu, Ji Li, John Ghosen, Ming Zeng, John Stebbins, Paras N. Prasad, and Mark T. Swihart

Size-Dependent Heating of Magnetic Iron Oxide NP

Size-Dependent Heating of Magnetic Iron Oxide Nanoparticles.
Sheng Tong, Christopher A. Quinto, Linlin Zhang, Priya Mohindra, and Gang Bao