Wednesday 30 July 2014

Artificial Frustrated Systems

Focus on artificial frustrated systems.
J Cumings, L J Heyderman, C H Marrows and R L Stamps
New J. Phys. 16, 075016 (2014)
Artificial spin ices. (a) XMCD-PEEM image of artificial spin ice, captured in the so-called 'string regime' [7], while undergoing thermal relaxation from an energetically excited, saturated moment, configuration down to one of the two degenerate ground states. Nanomagnets with moments pointing towards the bottom/left appear in blue contrast, while nanomagnets with moments pointing up/right appear in red contrast. Scale bar 2 μm. (b) X-ray transmission micrograph of a CoFeB artificial square ice with the overlaid red gridlines showing the square lattice. Magnetic contrast is shown in the inset, where islands that have reversed under thermal excitation at 100 °C appear with bright contrast. Scale bar 1 μm. (c) Lorentz transmission electron micrograph of artificial kagome ice after thermal excitation. The magnetization direction within the arms of the array can be determined from the detailed intensity profile across the arm [8], allowing the magnetic charge at each vertex to be inferred. Positive and negative magnetic charges are indicated by the overlaid red and blue dots, showing that the sample is in the charge-ordered, kagome ice-II state. Scale bar 500 nm. (d) The number of configurations that can be created in an artificial square ice by an applied field is very sensitive to disorder. The diagram represents all possible configurations that can be realized by application of the field (with magnitude slightly larger than the mean coercive field) to sixteen elements starting from a saturated type II state with a distribution of switching fields. Each unique configuration is indicated by a circular dot


Magnetic Nanoparticles: a Review

Magnetic Nanoparticles: A Subject for Both Fundamental Research and Applications.
S. Bedanta, A. Barman, W. Kleemann, O. Petracic, and T. Seki
Journal of Nanomaterials 952540 (2013)

The 2014 Magnetism Roadmap

The 2014 Magnetism Roadmap.

Robert L Stamps, Stephan Breitkreutz, Johan Åkerman, Andrii V Chumak, YoshiChika Otani, Gerrit E W Bauer, Jan-Ulrich Thiele, Martin Bowen, Sara A Majetich, Mathias Kläui, Ioan Lucian Prejbeanu, Bernard Dieny, Nora M Dempsey and Burkard Hillebrands
Journal of Physics D 47, 333001 (2014)

Saturday 26 July 2014

Imaging Spin waves

Close-up on spin dynamics.
Stanislas Rohart and Guillemin Rodary
Nature Materials 13, 770 (2014)

Imaging of spin waves in atomically designed nanomagnets.
A. Spinelli, B. Bryant, F. Delgado, J. Fernández-Rossier and A. F. Otte
Nature Materials 13, 782 (2014)

Tuesday 22 July 2014

Multiferroics and spin: A Review

Multiferroics of spin origin.
Yoshinori Tokura, Shinichiro Seki, and Naoto Nagaosa

Rep. Prog. Phys. 77, 076501 (2014)

The 2014 Magnetism Roadmap.

The 2014 Magnetism Roadmap.
Robert L Stamps, Stephan Breitkreutz, Johan Åkerman, Andrii V Chumak, YoshiChika Otani, Gerrit E W Bauer, Jan-Ulrich Thiele, Martin Bowen, Sara A Majetich, Mathias Kläui, Ioan Lucian Prejbeanu, Bernard Dieny, Nora M Dempsey and Burkard Hillebrands

J. Phys. D 47, 333001 (2014)

Friday 18 July 2014

Fast time evolution of noneq spins states

Theory of fast time evolution of nonequilibrium spin states in magnetic heterostructures.
I. A. Yastremsky, Peter M. Oppeneer, and B. A. Ivanov
Phys. Rev. B.90, 024409 (2014)
Time evolutions of the total magnetization in the Ni layer from its initial value, both for parallel and antiparallel configurations (ɛ=0.1) The dashed line presents the approximate result from Eq. (10). Note that here and henceforth in corresponding figures the value of the function MNi(t) at t=0 is chosen as zero, i.e., only the essential remagnetization dynamics is shown.

Thermal gradient DW motion

Thermodynamic theory for thermal-gradient-driven domain-wall motion.
X. S. Wang and X. R. Wang

http://doi.dx.org/10.1103/PhysRevB.90.014414

Thursday 10 July 2014

Au@Co3O4 NP for catalysis

Synthesis of Monodispere Au@Co3O4 Core-Shell Nanocrystals and Their Enhanced Catalytic Activity for Oxygen Evolution Reaction.
Zhongbin Zhuang, Wenchao Sheng and Yushan Yan
Novel OER catalysts – monodisperse Au@Co3O4 core-shell nanocrystals – have been prepared by synthesizing Au nanocrystals, followed by deposition of Co shells and their conversion to Co3O4 shells. Owing to the synergistic effect, Au@Co3O4 nanocrystals have an OER activity 7 times as high as a Au and Co3O4 nanocrystals mixture or Co3O4 nanocrystals alone, and 55 times as high as Au nanocrystals alone

Thermally assisted skyrmion motion

Thermally assisted current-driven skyrmion motion.
Roberto E. Troncoso, and Alvaro S. Núñez

Phys. Rev. B 89, 224403 (2014)