Quantum simulation of magnetism using 2D ion crystal

Simulating Magnetism (N&V)
Chrsitian Roos
Nature 484, 461 (2012)

Vibrational modes of a two-dimensional ion crystal. a, Equilibrium positions of the ions in a two-dimensional crystal after laser cooling. b, Four of the many vibrational modes of the crystal. Colours indicate whether an ion is above or below its equilibrium position at the particular time that is represented

Engineered two-dimensional Ising interactions in a trapped-ion quantum simulator with hundreds of spins.
Joseph W. Britton, Brian C. Sawyer, Adam C. Keith, C.-C. JosephWang, James K. Freericks, Hermann Uys, Michael J. Biercuk & John J. Bollinger
Nature 484, 489 (2012)

Approaches to Synthesis and Characterization of Spherical and Anisometric Metal Oxide Magnetic Nanomaterials - Nanotechnologies for the Life Sciences - Suber - Wiley Online Library

Approaches to Synthesis and Characterization of Spherical and Anisometric Metal Oxide Magnetic Nanomaterials.
Lorenza Suber, Davide Peddis

Nanotechnologies for the Life Sciences, Wiley online book (2012)

Theoretical approach to self-assembly and pattern formation

A compilation of articles by a Swedish group (Göteborg) related to the formation and design of patterns formed by particles by self-assembly, original!:

Isotropic potentials that cause particles
to self-assemble into snub square (a) and honeycomb (b) lattices.

Chiral Surfaces Self-Assembling in One-Component Systems with Isotropic Interactions
E. Edlund, O. Lindgren, and M. Nilsson Jacobi
Phys. Rev. Lett. 108, 165502 (2012)

Novel Self-Assembled Morphologies from Isotropic Interactions
E. Edlund, O. Lindgren, and M. Nilsson Jacobi
Phys. Rev.Lett.107, 085501 (2011)

Designing Isotropic Interactions for Self-Assembly of Complex Lattices
E. Edlund, O. Lindgren, and M. Nilsson Jacobi
Phys. Rev. Lett.107, 085503 (2011)

Universality of Striped Morphologies
E. Edlund and M. Nilsson Jacobi
Phys. Rev. Lett.105,137203 (2010)

Skyrmion lattice and helimagnetism in Cu2OSeO3

Long wavelength helimagnetic order and skyrmion lattice phase in Cu2OSeO3.
T. Adams, A. Chacon, M. Wagner, A. Bauer, G. Brandl, B. Pedersen, H. Berger, P. Lemmens, and C. Pffeiderer
ArXiv 1204.3597 (2012)

Magnetic phase diagram of Cu2OSeO3 as a function of applied magnetic field for various
orientations inferred from the magnetisation. (a) Overview for eld parallel h111i. Panels (b) through (d): Phase diagram
in the vicinity of Tc for various orientations. Di fferences as a function of eld are mostly due to demagnetising e ffects;
the brown shading indicates the regime of nearly critical spin fluctuations.

Modeling vortices in nanodisks by simulations

I have compiled a collection of articles from the Brazilian group of B. V. Costa and collegues on the subject of simulation of vortex structures on nanodots. I hope they will be of interest to you:

Analytical and Monte Carlo study of two antidots in magnetic nanodisks
with vortex-like magnetization
A. R. Pereira, A. R. Moura, W. A. Moura-Melo, D. F. Carneiro, S. A. Leonel and P. Z. Coura
J. Appl. Phys. 101, 034310 (2007)

A model for vortex formation in magnetic nanodots
S. A. Leonel, I. A. Marques, P. Z. Coura, and B. V. Costa
J. Appl. Phys. 102, 104311 (2007)

Diagram for vortex formation in quasi-two-dimensional magnetic dots
J. C. S. Rocha, P. Z. Coura, S. A. Leonel, R. A. Dias, and B. V. Costa
J. Appl. Phys. 107, 053903 (2010)

Magnetic vortex formation and gyrotropic mode in nanodisks.
D. Toscano, S. A. Leonel, R. A. Dias, P. Z. Coura, J. C. S. Rocha  and B. V. Costa
J. Appl. Phys. 109, 014301 (2011)

Magnetization dynamics of Co antidots

Optically Induced Tunable Magnetization Dynamics in Nanoscale Co Antidot Lattices.
Ruma Mandal, Susmita Saha, Dheeraj Kumar, Saswati Barman, Semanti Pal, Kaustuv Das,Arup Kumar Raychaudhuri, Yasuhiro Fukuma, YoshiChika Otani, and Anjan Barman
ACS Nano 6, 3397 (2012)

We report the time-domain measurements of optically induced precessional dynamics in a series of Co antidot lattices with fixed antidot diameter of 100 nm and with varying lattice constants (S) between 200 and 500 nm. For the sparsest lattice, we observe two bands of precessional modes with a band gap, which increases substantially with the decrease in S down to 300 nm. At S = 200 nm, four distinct bands with significant band gaps appear. The numerically calculated mode profiles show various localized and extended modes with the propagation direction perpendicular to the bias magnetic field. We numerically demonstrate some composite antidot structures with very rich magnonic spectra spreading between 3 and
27 GHz based upon the above experimental observation.

Fe oxide nanocubes with high SAR doe hyperthermia

Water-Soluble Iron Oxide Nanocubes with High Values of Specific Absorption Rate for Cancer Cell Hyperthermia Treatment.
Pablo Guardia, Riccardo Di Corato, Lenaic Lartigue, Claire Wilhelm, Ana Espinosa, Mar Garcia-Hernandez, Florence Gazeau, Liberato Manna, and Teresa Pellegrino
ACS Nano 6, 3080 (2012)

Iron oxide nanocrystals (IONCs) are appealing heat mediator nanoprobes in magnetic-mediated hyperthermia for cancer treatment. Here, specific absorption rate (SAR) values are reported for cube-shaped water-soluble IONCs prepared by a one-pot synthesis approach in a size range between 13 and 40 nm. The SAR values were determined as a function of frequency and magnetic field applied, also spanning technical conditions which are considered biomedically safe for patients. Among the different sizes tested, IONCs with an average diameter of 19 ± 3 nm had significant SAR values in clinical conditions and reached SAR values up to 2452 W/g_Fe at 520 kHz and 29 kAm^–1, which is one of the highest values so far reported for IONCs. In vitro trials carried out on KB cancer cells treated with IONCs of 19 nm have shown efficient hyperthermia performance, with cell mortality of about 50% recorded when an equilibrium temperature of 43 °C was reached after 1 h of treatment.

Perpective on Nanoferronics

Nanoferronics is a winning combination.
Manuel Bibes
Nature Mater.11, 354 (2012)

Interplay between ferroelectricity and magnetism at different kinds of interface. Depending on the direction of the ferroelectric polarization, a magnetic property is modified in the adjacent material. a, Controlling the Curie temperature across an interface. b, Turning magnetism on and off. c, Altering the spin polarization of electrons. d, Changing exchange coupling between magnetic layers.

Spintronics Insight special at Nature Materials

This is a must, one of the essential entries of the year.
Spintronics insight : Nature Materials, Full pdf version

Including the following articles:

New moves of the spintronics tango.
Jairo Sinova and Igor Žutić

Current-induced torques in magnetic materials.
Arne Brataas, Andrew D. Kent and Hideo Ohno  

Spin Hall effect devices.
Tomas Jungwirth, Jörg Wunderlich and Kamil Olejník

Spin caloritronics.
Gerrit E. W. Bauer, Eiji Saitoh and Bart J. van Wees

Silicon spintronics.
Ron Jansen

Spintronics and pseudospintronics in graphene and topological insulators.
Dmytro Pesin and Allan H. MacDonald

Skyrmion collapse in AFs

Collapse of Skyrmions in 2d Ferro- and Antiferromagnets.
Liufei Cai, Eugene M. Chudnovsky, and D. A. Garanin
ArXiv 1204.4848 (2012)

 

EB in core/shell AFM/FM NPs

Modeling of exchange bias in the antiferromagnetic (core)/ferromagnetic (shell) nanoparticles with specialized shapes.
Yong Hu,  Yan Liu, An DuJMMM 323, 2613 (2012)

 Snapshots of the spin configurations in the vertical section central plane through the symmetry axis of ellipsoid-shaped nanoparticle with K_C=0.5 in different fields around the coercive fields of field-cooled hysteresis loop. Hl and Hr are the fields around the coercive fields at the descending and ascending branches, respectively. (a) Hl=−0.07, (b) Hl=−0.08, (c) Hl=−0.09, (d) Hl=−0.10, (e) Hl=−0.11, (f) Hr=0.03, (g) Hr=0.05, (h) Hr=0.07, (i) Hr=0.08, (j) Hr=0.09.

Nonlinear gyration of a vortex

Nonlinear magnetic vortex gyration.
André Drews, Benjamin Krüger, Gunnar Selke, Thomas Kamionka, Andreas Vogel, Michael Martens, Ulrich Merkt, Dietmar Möller, and Guido Meier
Phys. Rev. B 85, 144417 (2012)

(a) Simulated trajectory (blue triangles) and trajectory obtained from Eq. (3) (solid line) in a permalloy square
with an edge length of 200 nm and a thickness of 10 nm. The dashed line denotes the solution for vanishing nonquadratic terms of the potential. The vortex is excited with j0 = 1 × 1011 Am−2 and gyrates resonantly at = 2.56 × 109 s−1 (2.71 × 109 s−1) for vanishing (nonvanishing) nonlinear terms. (b) Simulated magnetization patterns and corresponding isolines in the steady state at instants of time t = 0.57T , 0.74T , and 0.84T of one gyration period T.

FM resonance detection through thermoelectric effecet

Thermoelectric Detection of Ferromagnetic Resonance of a Nanoscale Ferromagnet.
F. L. Bakker,* J. Flipse, A. Slachter, D. Wagenaar, and B. J. van Wees
Phys. Rev. Lett. 108, 167602 (2012)

(a) Series of Seebeck voltage versus magnetic field measurements for 11 different frequencies. The traces are offset by 150 nV for clarity. Because of the modulation technique using two driving frequencies that are 5 GHz apart, peaks and dips are observed at the resonance fields for both frequencies. (b) Frequency versus the magnetic field at the center of the resonance peak. The line corresponds to a fit of the Kittel equation. (c) Generated power and corresponding Seebeck voltage calculated using Eq. (5) and thermoelectric finite-element modeling for multiple frequencies. The measured peak heights of (a) are indicated by the black dots.

Including higher order anisotropy in modelling of hysteresis of NPs

Efficient hysteresis loop simulations of nanoparticle assemblies beyond the uniaxial anisotropy.
Alexandre Tamion, Edgar Bonet, Florent Tournus, Cécile Raufast, Arnaud Hillion, Oksana Gaier, and Véronique Dupuis
Phys. Rev. B 85, 134430 (2012)

Left: ZFC/FC magnetization curves and superparamagnetic m(H) at 300 K (in inset) of the Co :C. Right: Hysteresis loops at 2 K. The solids line correspond to the fits. The astroids associated with the biaxial fits are
shown in inset together with an enlargement of the merging region.

Hollow Iron Oxide Nanoparticles for Application in Lithium Ion Batteries - Nano Letters (ACS Publications)

Hollow Iron Oxide Nanoparticles for Application in Lithium Ion Batteries.Bonil Koo, Hui Xiong, Michael D. Slater, Vitali B. Prakapenka, Mahalingam Balasubramanian, Paul Podsiadlo, Christopher S. Johnson, Tijana Rajh, and Elena V. Shevchenko
Nano Lett.,12, 2429 (2012)

Amount of intercalated/deintercalated Li⁺ ions as a function of cycle numbers at different rates (a) with different individual electrodes.

Single chain magnets as realization of 1D Ising and Heisenberg chains

A Stable Hybrid Bisphosphonate Polyoxometalate Single-Molecule MagnetHitoshi Miyasaka, Tomokura Madanbashi, Ayumi Saitoh, Natsuko Motokawa, Ryuta Ishikawa, Masahiro Yamashita, Stefan Bahr, Wolfgang Wernsdorfer, and Rodolphe Cl érac
Chemistry Eur. Journal 18, 3942 (2012)

A new functionalizable polyoxometalate platform: The heptanuclear Co^II polyoxometalate complex [{(B-α- PW₉O₃₄)Co₃(OH)(H₂O)₂(O₃PC(O)- (C₃H₆NH₃)PO₃)}₂Co]¹⁴⁻ represents a unique example of a magnetic, stable, functionalizable polyoxotungstate platform, and behaves as a single-molecule magnet.

Information transfer by spin chirality

Information transfer by vector spin chirality in finite magnetic chains.
Matthias Menzel, Yuriy Mokrousov, Robert Wieser, Jessica E. Bickel, Elena Vedmedenko, Stefan Blügel, Stefan Heinze, Kirsten von Bergmann, André Kubetzka, and Roland Wiesendanger
ArXiv 1204.2650 (2012)

SP-STM measurements of Fe chains on Ir(001). (a) and (b) Typical sample area of 30 x 30 nm2 measured with an Fe-coated
W tip without and with an applied external magnetic field of B = +2 T perpendicular to the sample surface, respectively (constant current images colorized with simultaneously acquired dI/dU maps, measurement parameters: U = +500mV, I = 5 nA, T = 8 K).(c) Topographic line profiles of the same Fe chain at B = 0 T and B = 2 T measured with a Cr-coated tip. The insets show schematically the tip magnetization and how a 120 deg spin-spiral, which is inverting in opposite fields, could explain the experimental results.

Skyrmions in Multiferroics

Observation of Skyrmions in a Multiferroic Material.
S. Seki, X. Z. Yu, S. Ishiwata, Y. Tokura
Science 336, 198 (2012)

Fig. 1. (A) Crystal structure of Cu2OSeO3, characterized by two inequivalent Cu2+ sites with different oxygen coordination. (B) Ferrimagnetic spin arrangement on Cu2+ sites. (C to G) Lateral magnetization distribution map for a thin-film (~100-nm-thick) sample of Cu2OSeO3, obtained through the analysis of Lorentz TEM data taken at 5 K. The color wheel in the bottom-left corner of (F) shows the direction (hue) and relative magnitude (brightness) of the lateral magnetization. Panels (C) and (D), as well as (F) and (G), represent images for the (110) and (111) plane, respectively, and a magnetic field is applied normal to the observed sample plane. In both cases, proper screw-spin texture appears for zero magnetic field, whereas a skyrmion lattice with the identical spin chirality is formed for H = 800 Oe. A magnified view of (D) is shown in (E), where white arrows represent the magnetization direction. (H) Schematic illustration of a single magnetic skyrmion.

A network approach to artificial spin ice

A network model for field and quenched disorder effects in artificial spin ice.
Zoe Budrikis, Paolo Politi and R L Stamps
New Journal Physics 14, 045008 (2012)

The network of states accessible from the +x polarized configuration (the large red node), at a field strength of h = 11.5, for (a) a perfect system and (b) a system where the lower-left corner island can be flipped independently of the others.

Toxicity of SPIONs

Assessing the In Vitro and In Vivo Toxicity of Superparamagnetic Iron Oxide Nanoparticles.
Morteza Mahmoudi, Heinrich Hofmann, Barbara Rothen-Rutishauser,|and Alke Petri-Fink
Chemical Reviews 112, 2323 (2012)

(a) Prominent in vitro assays that are used to probe the impact of nanomaterials on cells; (b) TEM micrograph of a human
liver cell line (HepG2) showing the mechanism of action of representative cell assays (i.e., MTT, checking mitochondria activity; PI, DNA staining; BrdU, DNA replication staining; LDH, membrane integrity assessment).

Review of Core/Shell Nanoparticles

A very complete review article focused on the synthesis, preparation methods, application and classification of all kind of core/shell NPs, not only magnetic:

Core/Shell Nanoparticles: Classes, Properties, Synthesis Mechanisms, Characterization, and Applications
Rajib Ghosh Chaudhuri and Santanu Paria
Chemical Reviews 112, 2373 (2012)

Different core/shell nanoparticles: (a) spherical core/shell NPs ; (b) hexagonal core/shell NPs; (c) multiple small core materials coated by single shell material; (d) nanomatryushka material; (e) movable core within hollow shell material.

Optical spin transfer torque observed

Experimental observation of the optical spin transfer torque.
P. Nemec1, E. Rozkotová, N. Tesarová, F. Trojánek, E. De Ranieri, K. Olejník, J. Zemen, V. Novák, M. Cukr, P. Malý and T. Jungwirth
Nature Physics AOL (2012)

Schematic illustration of the optical spin transfer torque. a, Schematic illustration of the optical spin transfer torque in the large spin lifetime limit. The rate P of the photo-carrier spin injection along the light propagation axis ˆn (normal to the sample plane) is completely transferred to the optical spin transfer torque (OSTT) acting along the normal to the sample plane on the magnetization M of the ferromagnet. The steady-state component of the injected spin density s0 is oriented in the plane of the sample and perpendicular to the in-plane equilibrium magnetization vector. The fast precessing component of the spin of a photo-carrier (small upper arrows) relaxes to the environment at a random orientation, producing a zero net momentum transfer to the environment. This picture applies to photo-electrons in (Ga, Mn)As. b, A weak torque acting on M (red arrow) produced by photo-carriers with a short spin lifetime. Most of the spin angular moment is transferred to the environment in this limit. For photo-holes in (Ga, Mn)As this picture is more relevant than the picture of the strong optical spin transfer torque shown in a.