Spin waves in permalloy nanowires: The importance of easy-plane anisotropy

Nguyen, T. M.; Cottam, M. G.; Liu, H. Y.; Wang, Z. K.; Ng, S. C.; Kuok, M. H.; Lockwood, D. J.; Nielsch, Kornelius; Gösele, U.

doi:10.1103/physrevb.73.140402

Cited by 28 publications

(18 citation statements)

References 18 publications

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“…[16][17][18] Their dynamic magnetic properties have been probed by ferromagnetic resonance [19][20][21][22] and Brillouin light scattering. 24,25 From the theoretical point of view, the MNWA is a complicated object. The precessional mode spectrum of isolated magnetic nanowires of finite thickness has been considered analytically in Refs.…”

Section: Introductionmentioning

confidence: 99%

Static and dynamic magnetic properties of densely packed magnetic nanowire arrays

et al. 2013

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The static and dynamic magnetic properties of magnetic nanowire arrays with high packing density (>0.4) and wire diameter much greater than the exchange length have been studied by static and time-resolved magneto-optical Kerr effect measurements and micromagnetic simulations. The nanowires were formed by electrodeposition within a nanoporous template such that their symmetry axes lay normal to the plane of the substrate. A quantitative and systematic investigation has been made of the static and dynamic properties of the array, which lie between the limiting cases of a single wire and a continuous ferromagnetic thin film. In particular, the competition between anisotropies associated with the shape of the individual nanowires and that of the array as a whole has been studied. Measured and simulated hysteresis loops are largely anhysteretic with zero remanence, and the micromagnetic configuration is such that the net magnetization vanishes in directions orthogonal to the applied field. Simulations of the remanent state reveal antiferromagnetic alignment of the magnetization in adjacent nanowires and the formation of vortex flux closure structures at the ends of each nanowire. The excitation spectra obtained from experiment and micromagnetic simulations are in qualitative agreement for magnetic fields applied both parallel and perpendicular to the axes of the nanowires. For the field parallel to the nanowire axes, there is also good quantitative agreement between experiment and simulation. The resonant frequencies are initially found to decrease as the applied field is increased from remanence. This is the result of a change of mode profile within the plane of the array from nonuniform to uniform as the ground state evolves with increasing applied field. Quantitative differences between experimental and simulated spectra are observed when the field is applied perpendicular to the nanowire axes. The dependence of the magnetic excitation spectra upon the array packing density is explored, and dispersion curves for spin waves propagating within the array parallel to the nanowire axis are presented. Finally, a tunneling of end modes through the middle region of the nanowires was observed. The tunneling is more efficient for wires forming densely packed arrays, as a result of the extended penetration of the dynamic demagnetizing fields into the middle of the wires and due to the lowering of the tunneling barrier by the static demagnetizing field of the array.

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Section: Introductionmentioning

confidence: 99%

Static and dynamic magnetic properties of densely packed magnetic nanowire arrays

et al. 2013

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“…Several routes have been developed for the preparation of such objects. 14,20 A rigorous analysis of the static and dynamic measurements requires then to take into account these dipolar interactions. [1][2][3][4][5][6][7][8][9] The static magnetic properties have been intensively studied by magnetometry experiments [1][2][3][4][5][6][7][8][9] while the dynamic magnetic properties have been probed by ferromagnetic resonance [10][11][12][13] and Brillouin light scattering [14][15][16] experiments.…”

Section: Introductionmentioning

confidence: 99%

Dipolar interactions in arrays of ferromagnetic nanowires: A micromagnetic study

Zighem

Maurer

Ott

et al. 2011

Journal of Applied Physics

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We explore the behavior of periodic arrays of magnetic nanowires by micromagnetic simulations using the NMAG modeling package. A large number of modeling studies on such arrays of nanowires have been performed using finite size models. We show that these finite size micromagnetic descriptions can only be used in specific situations. We perform a systematic study of more or less dense one-and two-dimensional arrays of nanowires using either finite size or infinite size models and we show that finite size models fail to capture some of the features of real infinite systems. We show that the mean field model scaled to the system porosity is valid. This work can be used as a basis to the extension of micromagnetic calculations of the magnetization dynamics in arrays of nanowires.

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“…Numerous experiments revealed ferromagnetic properties of nanomaterials, which are nonmagnetic in the bulk. For instance, remarkable room-temperature ferromagnetism was observed in undoped TiO 2 , HfO 2 , and In 2 O 3 thin films with extrapolated Curie temperatures far in excess of 400 K [1,2]. Magnetization of TiO 2 and HfO 2 films strongly decreases after 4 h annealing in oxygen and eventually disappears for 10 h annealing.…”

Section: Introductionmentioning

confidence: 99%

Anion vacancy-driven magnetism in incipient ferroelectric SrTiO3 and KTaO3 nanoparticles

Eliseev

Morozovska

Glinchuk

et al. 2011

Journal of Applied Physics

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Based on our analytical results [http://arxiv.org/abs/1006.3670], we predict that undoped nanoparticles (size ≤ 10 − 100 nm) of incipient ferroelectrics without any magnetic ions can become ferromagnetic even at room temperatures due to the inherent presence of a new type of magnetic defects with spin S=1, namely oxygen vacancies, where the magnetic triplet state is the ground state in the vicinity of the surface (magnetic shell), while the nonmagnetic singlet is the ground state in the bulk material (nonmagnetic core). Consideration of randomly distributed magnetic spins (S=1) had shown that magneticproperties of incipient ferroelectric nanoparticles are strongly size and temperature dependent due to the size and temperature dependence of their dielectric permittivity ( ) R T , ε and the effective Bohr. The phase diagrams in coordinates temperature and particle radius are considered. In particular, for particle radii R less that the critical radius ) (T R c ferromagnetic longrange order appears in a shell region of thickness 5 -50 nm once the concentration of magnetic defects N exceeds the magnetic percolation threshold

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Spin waves in permalloy nanowires: The importance of easy-plane anisotropy

Cited by 28 publications

References 18 publications

Static and dynamic magnetic properties of densely packed magnetic nanowire arrays

Static and dynamic magnetic properties of densely packed magnetic nanowire arrays

Dipolar interactions in arrays of ferromagnetic nanowires: A micromagnetic study

Anion vacancy-driven magnetism in incipient ferroelectric SrTiO3 and KTaO3 nanoparticles

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