MOKEstudy of artificial spin ice

Magneto-optical Kerr effect studies of square artificial spin ice.
K. K. Kohli, Andrew L. Balk, Jie Li, Sheng Zhang, Ian Gilbert, Paul E. Lammert, Vincent H. Crespi,
Peter Schiffer, and Nitin Samarth
Phys. Rev. B 84, 180412(R) (2011)

(a) Variation of coercivity at θ = 0 as a function of lattice spacing for square arrays. Measurements on various samples (arrays 1–4) are compared with micromagnetic simulations (black squares), comparing simulations of the same island outlines but with different spacing.  (b) Experiment and simulation for square arrays as a function of angle for the largest lattice spacing of 880 nm.

Supra Nanocrystallinities

Supra- and nanocrystallinities: a new scientific adventure.
M P Pileni
J. Phys. CM 23, 503102 (2011)

Typical morphologies of nanoparticles that are either single-domain nanocrystals. Calculated absorption spectra of (f) Au, (g) Ag and (h) Cu nanoparticles with cuboctahedral (blue), truncated octahedral (pink), decahedral (red) and icosahedral (green) morphologies.

Ultrafast magnetization dynamics: a Review

Electron theory of fast and ultrafast dissipative magnetization dynamics.
M Fähnle and C Illg
J. Phys. CM 23, 493201 (2011)

(a) A sketch of the equilibrium Fermi surface S for time t-dt and time t. In a strict equilibrium situation the yellow
states are occupied only at time t-dt, the red are occupied only at time t, whereas the blue states are occupied at both times. Panel (b) shows a sketch of the equilibrium band structure.

Ground state formation in artificial spin ice

Disorder strength and field-driven ground state domain formation in artificial spin ice: experiment, simulation and theory.
Zoe Budrikis, J.P. Morgan, J. Akerman, A. Stein, R.L. Stamps, Paolo Politi, S. Langridge, and C.H. Marrows
ArXiv 1111.6491 (2011)

MFM images of final states of open (a-d) and closed (e-h) arrays after rotation at selected hold fields. The black outline in (g) indicates a GS domain.

Quantum effects in a magnetic vortex

Quantum depinning of the magnetic vortex core in micron-size permalloy disks.
Ricardo Zarzuela, Saül Vélez, Joan Manel Hernandez, Javier Tejada, and Valentyn Novosad
Phys. Rev. B 85, 180401(R) (2012)

Temperature dependence of the magnetic viscosity S(T ) at H = 0 and 300 Oe.

Reversal in individual and interacting NPs

Magnetization reversal in isolated and interacting single-domain nanoparticles.
H. Kesserwan, G. Manfredi, J.-Y. Bigot, and P.-A. Hervieux
Phys. Rev. B 84, 172407 (2011)

Relaxation times for isolated NPs (circles) and interacting NPs for different interparticle distances: d = 9.6 nm (squares), d = 11.8 nm (triangles), and d =16.6 nm (stars). The occupation probability is p = 0.5. The damping constant is α = 1.

Finite-size effect on Tc of Ni NPs

Finite-size scaling behavior and intrinsic critical exponents of nickel: Comparison with the three-dimensional Heisenberg model.
Jun Wang, Wei Wu, Fan Zhao, and Guo-meng Zhao
Phys. Rev. B 84, 174440 (2011)

(a) Plot of T_C versus the mean diameter of the Ni NPs. The best fit yields ν = 1.06 ±0.07 and ξ0 = 0.65 ± 0.10 nm. (b) Same for Ni nanowires. The best fit yields ν = 1.03 ± 0.05 and ξ0 = 2.4 ± 0.4 nm.

Lage self-assemblies of NPs

Ultra-Large-Area Self-Assembled Monolayers of Nanoparticles.
Tianlong Wen and Sara A. Majetich
ACS Nano 5, 8868 (2011)

Ab initio couplings in Fe

Magnetoelastic coupling in gamma-iron.
S. V. Okatov, Yu. N. Gornostyrev, A. I. Lichtenstein, M. I. Katsnelson
ArXiv 1111.4432 (2011)

The exchange parameter as a function of interatomic distance to the n-th neighbour Jn(Rn) for different c/a ratios.

Effect of current on energy barrier for DW pinning

Electric Current Effect on the Energy Barrier of Magnetic DomainWall Depinning: Origin of the Quadratic Contribution.
Kab-Jin Kim, Jisu Ryu, Gi-Hong Gim, Jae-Chul Lee, Kyung-Ho Shin, Hyun-Woo Lee, and Sug-Bong Choe
Phys. Rev. Lett. 107, 217205 (2011)

(a) Two-dimensional map of E_B as a function of H and J. (b) E_B vs J at several bias H. The solid lines are the best fit with Eq. (2).

Magnetic and structural order in Mn3O4

Pressure and field tuning the magnetostructural phases of Mn3O4: Raman scattering and x-ray diffraction studies.
M. Kim, X. M. Chen, X. Wang, C. S. Nelson, R. Budakian, P. Abbamonte, and S. L. Cooper
Phys. Rev. B 84, 174424 (2011)

Contour plots of the T2g(1) phonon mode intensities as functions of energy and field (e) Illustrations of theMn3O4 structure in (I) the orthorhombicwithmagnetic easy axis along [110], (II) tetragonal, and (III) orthorhombic structure of Mn3O4 with magnetic easy axis along [110]. (f) H-T phase diagram.

Control of damping with metamaterials

Control of Gilbert damping using magnetic metamaterials.
Chiharu Mitsumata, Satoshi Tomita
Phys. Rev. B 84, 174421 (2011)

Comparison between Model 2 (green line and blue circles) and Model 3 (pink line and red triangles) when
r0 = 10. Effective Gilbert damping factor α  is obtained from the fitting curves.

Magnon damping from DFT

Different dimensionality trends in the Landau damping of magnons in iron, cobalt, and nickel: Time-dependent density functional study.
Paweł Buczek, Arthur Ernst, and Leonid M. Sandratskii
Phys. Rev. B 84, 174418 (2011)

Spin waves of fcc Co. Solid circles correspond to ω0(q), while the error bars denote full width at  half maximum (FWHM) of the peak. Solid line denotes SW energies obtained from MFT. Solid triangles stand for the experimental estimation of the dispersion relation by Balash.

TM oxides by ab initio DFT calculations

Magnon spectrum of transition-metal oxides: Calculations including long-range magnetic interactions using the LSDA + U method.
F. Essenberger, S. Sharma, J. K. Dewhurst, C. Bersier, F. Cricchio, L. Nordström, and E. K. U. Gross
Phys. Rev. B 84, 174425 (2011)

N´eel temperatures as a function of U for NiO, CoO, and MnO. The dashed lines denote the experimental values and the gray solid lines are Monte Carlo simulations.

Magnetoelastic metamaterials

Magnetoelastic metamaterials.
Mikhail Lapine, Ilya V. Shadrivov, David A. Powell and Yuri S. Kivshar
Nature Mater. 11,30 (2011)

An anisotropic magnetic metamaterial combined with an elastic medium. wo layers of the bulk sample are shown. a, The metamaterial before the electromagnetic field is applied. b, The metamaterial is compressed by the electromagnetic forces acting between the elements. Dimensionless lattice parameters a and bare normalized to the resonator radius r₀.

Hybrid NP colloids

A total-synthesis framework for the construction of high-order colloidal hybrid nanoparticles.
Matthew R. Buck, James F. Bondi and Raymond E. Schaak
Nature Chem. 4, 37 (2012)

Schematic showing the multistep synthesis of M–Pt–Fe₃O₄ heterotrimers, along with the most significant possible products and their observed frequencies (expressed as the percentage of observed heterotrimers, not total yield).

SC vortex dynamics induced by micromagnets

Imaging the Statics and Dynamics of Superconducting Vortices and Antivortices Induced by Magnetic Microdisks.
R. B. G. Kramer, A.V. Silhanek, W. Gillijns, and V.V. Moshchalkov
Phys. Rev. X 1, 021004 (2011)

Probing the mobility of vortex-antivortex pairs. (a), (d) Scanning Hall Microscopy images at H=0 and T=6.9 K for two different magnetic moments of the disks. (b),(e) Scanning ac-susceptibility images taken with h=0.2 Oe and h=0.6 Oe, and a frequency of excitation 77 Hz. Panels (c) and (f ) show a superposition of panels (a) and (b), and (d) and (e).

Co-W NPs

Structural and magnetic properties of amorphous Co-W alloyed nanoparticles.
A. I. Figueroa, J. Bartolomé, L. M. García, F. Bartolomé, C. Magén,A. Ibarra, L. Ruiz, J. M. González-Calbet, F. Petroff, C. Deranlot, S. Pascarelli, P. Bencok, N. B. Brookes, F. Wilhelm, and A. Rogalev
Phys. Rev. B 84, 184423 (2011)

Dependence of Keff with mL/mS for the a series of Co-W samples and comparison with those for the bulk Co
(Ref. 67), bare Co NPs with tCo = 0.7 nm (Ref. 14), and Co-Pt NPs with comparable diameters (Ref. 16).

Manipulating molecular magnets by Landau-Zener

Manipulation of the spin in single molecule magnets via Landau-Zener transitions
Andrew Palii, Boris Tsukerblat, Juan M. Clemente-Juan, Alejandro Gaita-Ariño, and Eugenio Coronado
Phys. Rev. B 84, 184426 (2011)

Schematic image of the Fe8 SMM: combined action of a longitudinal dc magnetic field (applied along the easy axis of the magnetization) and a pulse of the field directed against the dc field.

E field induced reversal in FM-Multiferroic

Electric-Field-Induced Magnetization Reversal in a Ferromagnet-Multiferroic Heterostructure
J. T. Heron, M. Trassin, K. Ashraf, M. Gajek, Q. He, S.Y. Yang, D. E. Nikonov, Y-H. Chu, S. Salahuddin, and R. Ramesh
Phys. Rev. Lett. 107, 217202 (2011)

(a) In-plane hyst. curves at room T CoFe/BFO heterostructures. (b) In-plane PFM image of BFO. (c) XMCD-PEEM image of the CoFe/BFO heterostructure.

Disorder and the Ground State in Artificial Spin Ice

Diversity Enabling Equilibration: Disorder and the Ground State in Artificial Spin Ice.
Zoe Budrikis, Paolo Politi, and R. L. Stamps
Phys. Rev. Lett. 107, 217204 (2011)

Left: For an undisordered system, clockwise rotating fields, anticlockwise rotating fields, and a field protocol that alternates sense of rotation every 2 cycles all give the same final energy. Right: The subnetwork of states that can beaccessed from the þx saturated configuration for (a) a perfect system (where the saturated configuration is the large red node) and (b) a typical disordered system.

Muons in spin ice

Monopoles, magnetricity and the stray field from spin ice.
Stephen J. Blundell 
Phys. Rev. Lett. 108, 147601 (2012)
ArXiv 1111.3657 (2011)

Distribution of B_mu in the vicinity of (a-c) two spins at positions (+-a; 0; 0), showing the field in the y = 0 (left) and x = 0 (right) planes, and (d-e) fourspins on the corners of a tetrahedron (inscribed in a cube of side length d, centered at the origin), satisfying the ice rules.

Quantum, shape and size effects in magnetization reversal

Macrospin approximation and quantum effects in models for magnetization reversal.
Mohammad Sayad, Daniel G¨utersloh and Michael Potthoff
ArXiv 1111.3900 (2011)

Sketch of the different magnetization-reversal mechanisms in the classical model for anisotropy strength D
smaller (macrospin model, coherent rotation) or larger (nucleation) than the critical value Dc and for infinite D (nucleation, vanishing domain-wall width) as verified by calculations for L = 4 spins.

Magnetite NPs by decarboxylation

Reduction of iron by decarboxylation in the formation of magnetite nanoparticles.
Nicolás Pérez, Francisco López-Calahorra, Amílcar Labarta and Xavier Batlle
Phys. Chem. Chem. Phys. 13, 19485 (2011)

TEM images of: (a) decomposition of Fe(III) acetylacetonate with decanoic acid in benzylether, NP1; (b) decomposition of Fe(III) decanoate with decanoic acid in benzylether, NP2; (c) conventional decomposition of Fe(III) decanoate, NP3.

Hollow inorganic spheres: A Review

Fabrication and application of inorganic hollow spheres.
Jing Hu, Min Chen, Xiaosheng Fang and Limin Wu
Chem. Soc. Rev. 40, 5472 (2011)

Labyrinthine Magnetic Domains in films

Nucleation and avalanches in films with labyrinthine magnetic domains.
A. Benassi, S. Zapperi
ArXiv 1111.3140 (2011)

Hysteresis loops for di erent dipolar interaction strength. The inset sketches our model ferromagnetic thin lm. Panels (a-h) lm magnetization m(x; y) for di fferent external field values along the hysteresis loop.

Magnetic capsules for NMR

Magnetic Capsules for NMR Imaging: Effect of Magnetic Nanoparticles Spatial Distribution and Aggregation.
Azhar Zahoor Abbasi, Lucía Gutierrez, Loretta L. del Mercato, Fernando Herranz, Oksana Chubykalo-Fesenko, Sabino Veintemillas-Verdaguer, Wolfgang J. Parak,M Puerto Morales, Jesus M Gonzalez, Antonio Hernando, and Patricia de la Presa
J. Phys. Chem. C 115, 6257 (2011)

Protein corona in NPs

Hardening of the Nanoparticle–Protein Corona in Metal (Au, Ag) and Oxide (Fe 3 O 4 , CoO, and CeO 2 ) Nanoparticles.
Eudald Casals , Tobias Pfaller , Albert Duschl , Gertie J. Oostingh ,and Víctor F. Puntes
Small 7, 3479 (2011)

NP–protein interactions. The process of conjugation of the NP when inserted in biological media takes few minutes in the working conditions (I), which evolves to a NP coated with protein in equilibrium with the proteins in the medium (II), then later evolves towards an irreversible protein corona with proteins that are no longer in equilibrium with
their in-solution counterparts (III).

Biotemplated NP Arrays

Biotemplated Magnetic Nanoparticle Arrays.
Johanna M. Galloway , Jonathan P. Bramble , Andrea E. Rawlings , Gavin Burnell, Stephen D. Evans, and Sarah S. Staniland
Small 8, 204 (2011)

Immobilized biomineralizing protein Mms6 templates the formation of uniform magnetite nanoparticles in situ when selectively patterned onto a surface. Magnetic force microscopy shows that the stable magnetite particles maintain their magnetic orientation at room temperature, and may be exchange coupled. This precision-mixed biomimetic/soft-lithography methodology offers great potential for the future of nanodevice fabrication.

Proximity effects in topological insulators

Magnetic Proximity Effect as a Pathway to Spintronic Applications of Topological Insulators.
Ivana Vobornik,Unnikrishnan Manju, Jun Fujii, Francesco Borgatti, Piero Torelli, Damjan Krizmancic, Yew San Hor, Robert J. Cava, and Giancarlo Panaccione
Nano Letters 11, 4079 (2011)

Mn and Fe XMCD hysteresis loops vs temperature for Fe (black) and Mn (red).

Sailing plasmonic NP

Plasmonic Nanoparticle Chain in a Light Field: A Resonant Optical Sail.
Silvia Albaladejo, Juan José Sáenz, and Manuel I. Marqués
Nano Lett 11, 4597 (2011)

We propose to use a chain made of metallic nanoparticles as a resonant light sail, attached by one end point to a transparent object and propelling it by the use of electromagnetic radiation.

Plasmonic nanoclusters by DNA

DNA-Enabled Self-Assembly of Plasmonic Nanoclusters.
Jonathan A. Fan, Yu He, Kui Bao, Chihhui Wu, Jiming Bao, Nicholas B. Schade, Vinothan N. Manoharan, Gennady Shvets, Peter Nordlander, David R. Liu, and Federico Capasso
Nano Letters 11, 4859 (2011)

DNA-mediated assembly of plasmonic heterotetramers.

Gold NPs for medicine

Gold Nanoparticles: A Revival in Precious Metal Administration to Patients.
A. S. Thakor, J. Jokerst, C. Zavaleta, T. F. Massoud, and S. S. Gambhir
Nano Letters 11, 4029 (2011)

Suppression of thermal stability by rotating field.

Resonant suppression of thermal stability of the nanoparticle magnetization by a rotating magnetic field.
S. I. Denisov, A. Yu. Polyakov, and T. V. Lyutyy
Phys. Rev. B 84, 174410 (2011)

Diagram of the precessional modes for σρ = +1. The regions in the h-ω plane where different P modes exist
at σρ = +1 are denoted as P+1 (white) and P +1 (light-green). The Q mode is realized in the white shaded region.

Ultrafast magnetization dynamics: theory Review + article

Electron theory of fast and ultrafast dissipative magnetization dynamics.
M. Fähnle and C. Illg
JPCM, 23 493201 (2011)

Frustrated magnet at ultrahigh fields

Magnetic Phases of a Highly Frustrated Magnet, ZnCr2O4, up to an Ultrahigh Magnetic Field of 600 T.
Atsuhiko Miyata, Hiroaki Ueda, Yutaka Ueda, Hironobu Sawabe, and Shojiro Takeyama
Phys. Rev. Lett. 107, 207203 (2011)

Magnetic phase diagram . Cross symbols indicate transition points observed by the Faraday rotation method.
Broken lines show anomalies appeared in the magneto-optical absorption.

EB in FeO NPs

Exchange bias in iron oxide nanoclusters.
Jorge Sánchez-Marcos, M Ángeles Laguna-Marco, Rocío Martínez-Morillas, Eva Céspedes, Félix Jiménez-Villacorta, Nieves Menéndez and Carlos Prieto
JPCM 23, 476003 (2011)

Loops of TAD.n-FeOx//CU10 sample at different temperatures between 2 and 100 K. Inset: temperature evolution of coercive and EB fields.

Magnetic Friction

Magnetic friction: From Stokes to Coulomb behavior.
Martin P. Magiera, Sebastian Angst, Alfred Hucht, and Dietrich E. Wolf
Phys. Rev. B 84, 212301 (2011)

Magnetic NPs: Two Reviews

Magnetic nanoparticles: recent advances in synthesis, self-assembly and applications.
Srikanth Singamaneni, Valery N. Bliznyuk, Christian Binek and Evgeny Y. Tsymbal
J. Mater. Chem. 21, 16819 (2011)

PEEM imageing of reversal in core/shell nwires

Photoemission electron microscopy of three-dimensional magnetization configurations in core-shell nanostructures.
Judith Kimling, Florian Kronast, Stephan Martens, Tim Böhnert, Michael Martens, Julia Herrero-Albillos, Logane Tati-Bismaths, Ulrich Merkt, Kornelius Nielsch, and Guido Meier
Phys. Rev. B 84, 174406 (2011)

(a) PEEM images of the core-shell wire recorded at the iron L3 edge and the nickel L3 edge (background extracted).
(b)–(e) Differential XMCD images of the iron oxide tube (left) and the nickel core (right) recorded at the respective absorption edges.