Friday 30 September 2011

Frozen spins in CoO by XMLD

Determination of the Fe magnetic anisotropies and the CoO frozen spins in epitaxial CoO/Fe/Ag(001).
J. Li, Y. Meng, J. S. Park, C. A. Jenkins, E. Arenholz, A. Scholl, A. Tan, H. Son, H. W. Zhao, Chanyong Hwang, Y. Z. Wu, and Z. Q. Qiu
Phys. Rev. B 84, 094447 (2011)
(a) The relative L3 ratio difference (DeltaR3) as a function of the CoO thickness. (b) Percentage of the CoO frozen
spins deduced from (a). (c) Uniaxial anisotropy field in Fig. 3(b) follows the CoO frozen spins.


EB and roughness in core/shell NPs

Influence of interfacial roughness on exchange bias in core-shell nanoparticles.
R. F. L. Evans, D. Bate, and R. W. Chantrell, R. Yanes and O. Chubykalo-Fesenko
Phys. Rev. B 84, 092404 (2011)

Hysteresis loops and visualizations of four typical particles, each with different interfaces. Each interface
structure gives rise to different hysteresis, with different degrees of exchange bias.

Wednesday 28 September 2011

Synthesis of uniform NPs: Review

Formation Mechanisms of Uniform Nanocrystals via Hot-Injection and Heat-Up Methods.
Soon Gu Kwon and Taeghwan Hyeon
Small 7, 268 (2011)

Tuesday 27 September 2011

EB in core/shell nanowires

Magnetic Core-Shell Structure and Proximity Effect in 7 nm Single-Crystal Co3O4 Nanowires.
Ping Lv, Yan Zhang, Rui Xu, Jia-Cai Nie, Lin He
ArXiv_1109.4989 (2011)
(a) M(H) curves at 5 K under ZFC and FC modes. For the FC hysteresis loop, the sample is cooled in HFC = 20 kOe from 100 K to 5 K. (b) Left Y-axis shows the ratio of pinned magnetic moments Pin = Mpin/MS at 5 K. The right Y-axis shows theexchange bias field HE and coercivity HC at 5 K.

Monday 26 September 2011

Co nanomagnets: a Review

Cobalt-based magnetic nanocomposites: fabrication, fundamentals and applications.
TianlongWen and Kannan M Krishnan
J. Phys. D 44 393001 (2011)

Saturday 24 September 2011

Dipolar interactions and Anisotropy effects in small clusters

Effect of anisotropy on small magnetic clusters.
Alfred Hucht, Sanjubala Sahoo, Shreekantha Sil, and Peter Entel
Phys. Rev. B 84, 104438 (2011)
Schematic picture of ICO (left) and CUBO (right) with labeling of each atomic site.

Friday 16 September 2011

SW bands in 2D magnonic crystal

Band Diagram of SpinWaves in a Two-Dimensional Magnonic Crystal.
S. Tacchi, F. Montoncello, M. Madami, G. Gubbiotti, G. Carlotti, L. Giovannini, R. Zivieri, F. Nizzoli,.Jain, A. O. Adeyeye, and N. Singh
Phys. Rev. Lett. 107, 127204 (2011)
Measured frequencies (dots) as a function of the SW wave vector along the principal directions of the 1st BZ, for an external magnetic field H=1.0 kOe. The calculated dispersion curves are also reported.

Shifted loops due to imprinted barriers at high fields

Shifted loops and coercivity from field-imprinted high-energy barriers in ferritin and ferrihydrite nanoparticles.
Nuno J. O. Silva, V. S. Amaral, A. Urtizberea, R. Bustamante, A. Millán, F. Palacio, E. Kampert, U. Zeitler, S. de Brion, Òscar Iglesias and A. Labarta.
Phys. Rev. B 84, 104427 (2011)
Dependence of the (a) coercive field HC and (b) loop shift HS on the maximum field Hmax in ferritin, for different cooling fields Hcool.


Magnetic relaxation and size-distribution

Effect of the size distribution of magnetic nanoparticles on metastability in magnetization relaxation.
Yoh Yamamoto and Kyungwha Park
Phys. Rev. B 84, 094415 (2011)
The ground-state spin configurations for the S = 1 ferromagnetic Blume-Capel model at T=0.

Mapping loose spin RKKY coupling

Spatial Fluctuations of Loose Spin Coupling in CuMn/Co Multilayers.
T. Saerbeck, N. Loh, D. Lott, B. P. Toperverg, A. M. Mulders, A. Fraile Rodrıíguez, J.W. Freeland, M. Ali, B. J. Hickey, A. P. J. Stampfl, F. Klose, and R. L. Stamps
Phys. Rev. Lett. 107, 127201 (2011)
(a) Schematic coupling of a PM Mn spin between two FM layers. (b) Calculated lateral variation of J_LSC at 30 K. (c) RKKY exchange fields acting on loose Mn atoms derived by fits to the experimental data. Black dots indicate (111) planes in the fcc lattice. The extended plateau on either side of the plot indicates Mn impurities in the direct vicinity of the Co layers experiencing direct magnetic exchange.

Wednesday 14 September 2011

Spin transfer in transverse DWs

Enhanced spin transfer torque effect for transverse domain walls in cylindrical nanowires.
Matteo Franchin, Andreas Knittel, Maximilian Albert, Dmitri S. Chernyshenko, Thomas Fischbacher, Anil Prabhakar, and Hans Fangohr
Phys. Rev. B 84, 094409 (2011)
The relaxed magnetization configurations for θP = 0◦ (a) and θP = 90◦ (b). The sketches on the corners of the
two figures show that the DW moves into the barrier to allow the magnetization to align along the pinning direction in the barrier.

DyPO4 and GdPO4 NPs: size-effects

Size-dependent magnetic ordering and spin dynamics in DyPO4 and GdPO4 nanoparticles.
Marco Evangelisti, Tibi G. Sorop, Oleg N. Bakharev, Dirk Visser, Adrian D. Hillier, Juan J. Alonso, Markus Haase, Lynn A. Boatner, and L. Jos de Jongh
Phys. Rev. B 84, 094408 (2011)
Temperature dependence of the experimental ZF magnetic heat capacities for DyPO4 (top) and GdPO4
(bottom) for both nanoparticles and bulk, compared to the MC simulations (lines).

Monday 12 September 2011

Spin-transfer-torque-induced phenomena

Special Section in J. Phys.D containing, among others, the following review articles:


1) A brief review of field- and current-driven domain-wall motion.
Junya Shibata, Gen Tatara and Hiroshi Kohno
JPD 44, 384004 (2011)
Schematic of the translation motion of the domain wall in a uniform magnetic field.

2) Current-induced domain wall motion in nanoscale ferromagnetic element. G Malinowski, O Boulle and M Kläui
JPD 44, 384005 (2011)
Schematic of a magnetic wire with domains. The colour and the arrows indicate the magnetization direction.

Dynamics in spin ice

Spin dynamics in the ordered spin ice Tb2Sn2O7.
Sylvain Petit, Pierre Bonville, Isabelle Mirebeau, Hannu Mutka, Julien Robert
ArXiv 1109.1960

Mapping of the powder average S(Q) in Tb2Sn2O7 measured at 1.3K (top) and 65mK (bottom).

Hyperthermia and structural properties of NPs

Correlating Magneto-Structural Properties to Hyperthermia Performance of Highly Monodisperse Iron Oxide Nanoparticles Prepared by a Seeded-Growth Route.
Michael Levy, Alessandra Quarta, Ana Espinosa, Albert Figuerola, Claire Wilhelm, Mar García-Hernández, Alessandro Genovese, Andrea Falqui, Damien Alloyeau, Raffaella Buonsanti, Pantaleo Davide Cozzoli, Miguel Angel García, Florence Gazeau, and Teresa Pellegrino
Chem. Mater. 23, 4170 (2011)

Strain maps of a single crystal iron oxide MNP. Superposed: ZFC/FC hysteresis loops for 18 nm FeO NPs

Dipolar interactions in 2D

Phase transition in two-dimensional magnetic systems with dipolar interactions.
L.A.S. Mól and B.V. Costa
ArXiv 1109.1840 (2011)
Phase diagram of the anisotropic Heisenberg model with dipolar interactions for fixed A/J = 1 in the (D/J, T) space. The black solid line represents the transition lines as obtained using a cut-off in the dipolar interactions and the solid black line are the results obtained when full long-range interactions are consider.

Friday 2 September 2011

Magnetic Skyrmions

Spontaneous atomic-scale magnetic skyrmion lattice in two dimensions.
Stefan Heinze, Kirsten von Bergmann, Matthias Menzel, Jens Brede, André Kubetzka, RolandWiesendanger, Gustav Bihlmayer and Stefan Blügel
Nature Phys. 7, 713 (2011)
The nanoskyrmion lattice of the Fe ML on Ir(111).