Giant moving vortex mass

Giant moving vortex mass in thick magnetic nanodots.
K. Y. Guslienko, G. N. Kakazei, J. Ding, X. M. Liu & A. O. Adeyeye
Scientific Reports 5, 13881 (2015)

The frequency of the lowest vortex gyrotropic mode vs. dot thickness, ω₀(L) 2p: red squares – the experimental data, blue solid line – the simulated frequencies, green solid line – the calculations according to Eq. (4) accounting vortex mass, black dashed line – calculations without accounting for the vortex mass.

Vortex dynamics in arrays of nanomagnets

Observation of vortex dynamics in arrays of nanomagnets.
W. Yu, P. S. Keatley, P. Gangmei, M. K. Marcham, T. H. J. Loughran, R. J. Hicken, S. A. Cavill, G. van der Laan, J. R. Childress, and J. A. Katine
Phys. Rev. B 91, 174425 (2015)

TRSKM images, XPEEM images, and SEM images of arrays of 250-nm squares with separation of 500 nm in (a) and (b), and 50 nm in (c). After acquisition of the TRSKM images in (a), the equilibrium state was reinitialized before acquiring the TRSKM images in (b). In all TRSKM images the horizontal white bar has length of 1 μm. In (c) the white arrows in the TRSKM images denote regions of contrast with size comparable to, or larger than, that of a single element, while the dashed white rectangle in the XPEEM image highlights a cluster of elements with vortex equilibrium states. (d) Enlarged view of (c), in which the black grid position is a guide to the eye to show where the individual elements lie, and the white boxes highlight regions of contrast

Switching of magnetic skyrmion cores in nanodots

Microwave-induced dynamic switching of magnetic skyrmion cores in nanodots.
Bin Zhang, Weiwei Wang, Marijan Beg, Hans Fangohr and Wolfgang Kuch

Appl. Phys. Lett. 106, 102401 (2015)

Spin dynamics of the skyrmion excited by an AC magnetic field hωz=hω sin(ωt) with hω=2.4×10−3 up to time 25 000 (∼16.5 ns for J = 1 meV and S = 1). Selected time evolution of the magnetization distribution with two examples: (a) ωa  = 3.6 × 10⁻³, taoff=1750 and (b) ωb  = 1.4 × 10⁻², tboff=5600 . The color-coded mz (out-of-plane) and mx (in-plane) components of the magnetization are displayed in the first and third line, respectively, while the second line displays a perspective view (topography) with the color code of mz . (c) Time trace of the magnetization component mz (top graph), the AC magnetic field (dashed lines), and the skyrmion number (both in bottom graph). Black and red lines refer to the data of the two different examples, while the black circles and red prisms indicate the times corresponding to the snapshots shown in (a) and (b), respectively

Collective dynamics of 2D ferromegnetic element arrays

Review: Magneto.optical measurements of collective spin dynamics of two-dimensional arrays of ferromagnetic elements.
Bivas Rana and Anjan Barman
Spin 3, 1330001(2013) 

(a) Simulated resonant modes for an array of 200nm square dots with 100nm interdot separations are plotted as a
function of the azimuthal angle ( ) of the bias field. (b) Powerand phase distributions of the simulated modes are shown for
four di®erent values of . The color scales are shown at the top right corner of the figure.

Optical activity in Magnetoplasmonic Nanodisks

High Magneto-Optical Activity and Low Optical Losses in Metal-Dielectric Au/Co/Au–SiO2 Magnetoplasmonic Nanodisks.
Juan Carlos Banthí, David Meneses-Rodríguez, Fernando García, María Ujué González, Antonio García-Martín, Alfonso Cebollada, Gaspar Armelles
Advanced Materials 24, OP36 (2012)

a) Sketch of the composition of the fabricated nanodisks. b) AFM image of a selected fabricated structure (15 nm Au/10 nm Co/20 nm SiO₂/15 nm Au).

Collective SW excitations in coupled nanodots

Collective spin-wave excitations in a two-dimensional array of coupled magnetic nanodots.
Roman Verba and Gennadiy Melkov, Vasil Tiberkevich and Andrei Slavin

Spin-wave absorption spectra (a) and mode
structure [(b) and (c)] in a magnetic dot array in a FM ground
state having one defect per 11 × 11 dots.

Phys. Rev. B 85, 014427 (2012)

Regions of stability of different ground
states of a magnetic dot array in zero applied field: above the solid blue line both the FM and the CAFM ground states are stable; below the solid blue line, but above the dashed red line only the
CAFM ground state is stable; below the dashed red line both FM and CAFM states are unstable and array switches to a state with in-plane direction of the dot static magnetization.

 

Ground state of magnetic dots in a triangular lattice

Ground states and magnetization process for an triangular lattice array of magnetic dots with perpendicular anisotropy.
V. E. Kireev, R. S. Khymyn, B. A. Ivanov, and C. E. Zaspel
ArXiv 1201.1747 (2012)

Minimal configurations for rectangular samples of different shapes.

Magnetoplasmonics with nano FMs

Designer Magnetoplasmonics with Nickel Nanoferromagnets.
Valentina Bonanni, Stefano Bonetti, Tavakol Pakizeh, Zhaleh Pirzadeh, Jianing Chen, Josep Nogués, Paolo Vavassori, O Rainer Hillenbrand, O Johan Åkerman, and Alexandre Dmitriev
Nano. Lett. 11, 533 (2011)

We introduce a new perspective on magnetoplasmonics in nickel nanoferromagnets by exploiting the phase tunability of the optical polarizability due to localized surface plasmons and simultaneous magneto-optical activity. We demonstrate how the concerted action of nanoplasmonics and magnetization can manipulate the sign of rotation of the reflected light’s polarization (i.e., to produce Kerr rotation reversal) in ferromagnetic nanomaterials and, further, how this effect can be dynamically controlled and employed to devise conceptually new schemes for biochemosensing.

Vortex superlattices

Spin-transfer torque and current-induced vortex superlattices in nanomagnets.
Oleksii M. Volkov, Volodymyr P. Kravchuk, Denis D. Sheka, and Yuri Gaididei
Phys. Rev. B 84, 052404 (2011)

Dependence of critical current J1 onthe nanodisk thickness for different disk diameters.

Sub 100 nm Nanodots

Printing of Sub-100-nm Metal Nanodot Arrays by Carbon Nanopost Stamps.

Sang Ho Lee,† Byungjin Cho,† Seungha Yoon,† Huisu Jeong,† Sangyong Jon,‡ Gun Young Jung,† Beong Ki Cho,† Takhee Lee,† and Won Bae Kim
ACS Nano 5 5543 (2011)

The printed Au nanodots show an average size of 35 nm.