Ferromagnetic nanowire-loaded membranes for microwave electronics

Darques, M.; Spiegel, Judith; Medina, Joaquín De La Torre; Huynen, Isabelle; Piraux, Luc

doi:10.1016/j.jmmm.2008.03.060

Cited by 92 publications

(54 citation statements)

References 13 publications

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“…They have potential uses as magnetic recording media that overcome the superparamagnetic limit faced by conventional thin film media 4,5 or as replacements for ferrite-based materials in microwave devices of reduced physical size such as circulators, variable attenuators, phase shifters, modulators, stop-band filters, and power absorbing terminals. [6][7][8] The main advantages of MNWA are their low cost of production and well-defined and robust remanent microwave absorption with a frequency that can be tuned through a large range by an appropriate choice of ferromagnetic material. The use of MNWA in microwave circulators that do not require an external bias field has already been demonstrated.…”

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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“…For over a decade there has been a growing interest in microwave response of magnetic NWs, stemming from basic and applied research [Boucher et al, 2010;Darques et al, 2009;Fert & Piraux, 1999]. One of the characteristic experiments in the microwave region (1-50GHz) is to study these nanostructured materials under a simultaneous presence of a uniform applied field, H, and an exciting microwave field usually applied perpendicular to H. The uniform field determines the natural precession frequency of the magnetization around the effective field which depends on: H, contributions due to shape anisotropy, dipolar interactions, crystal field, and magnetoelastic interactions.…”

Section: Ferromagnetic Resonance and Blocking In Nanomagnetismmentioning

confidence: 99%

“…The development of nano-patterned membranes and nanowires (NW) is based on the interest in basic and applied research ranging from spintronics [Fert, 2008], chemical [Casanova et al, 2008], biosensing [Orosco et al, 2009;Pacholski et al, 2006], semiconductor [Yang, et al, 2010] and microwave applications [Darques et al, 2009] among others [Ferain & Legras, 2009]. In particular, the study and applications of NWs has grown extensively during the last decades.…”

Section: Introductionmentioning

confidence: 99%

On the behavior of Ni Magnetic Nanowires as studied by FMR and the effect of “blocking”.

Ramos¹,

Brigneti²,

Biasi³

et al. 2011

Nanowires - Fundamental Research

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“…The main advantages of what we call magnetic nanowired substrates (MNWS) are that they present a zero-field microwave absorption frequency that can be easily tuned over a large range of frequencies [1], as well as being low cost and fast to produce over large areas as compared to standard ferrite devices. Conventional ferrite circulators [3] need to be biased by a magnetic field to operate.…”

Section: Introductionmentioning

confidence: 99%

“…This biasing field is generally provided by a permanent magnet and, in view of the volume reduction, much effort was done lately to design unbiased microwave circulators using hexaferrites [4] or ferromagnetic nanowires [5]. Such templates were recently used to design various microwave devices (reviewed in [1]), such as phase shifters [6], isolators [7] or circulators [5]. In this paper, we will discuss a new type of planar integrated microwave circulator of improved design, fabricated on porous alumina templates, as sketched in figure 1(b).…”

Section: Introductionmentioning

confidence: 99%

Microwave circulator based on ferromagnetic nanowires in an alumina template

et al. 2010

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Unbiased planar microwave circulators were fabricated by electrodeposition of NiFe nanowires into porous alumina templates. Microwave properties of the devices are seen to depend drastically on the height of the nanowires and the newly developed devices exhibit improved features, compared to existing nanowire-based designs. Thanks to the high anisotropy of the nanowires, zerofield circulation modes may be observed in a frequency range from 10 to 30 GHz, with isolation as large as 30 dB, as well as low insertion losses -5 dB, making it compatible with industrial needs for device applications. Abstract Unbiased planar microwave circulators were fabricated by electrodeposition of NiFe nanowires into porous alumina templates. Microwave properties of the devices are seen to depend drastically on the height of the nanowires and the newly developed devices exhibit improved features, compared to existing nanowire-based designs. Thanks to the high anisotropy of the nanowires, zero-field circulation modes may be observed in a frequency range from 10 to 30 GHz, with isolation as large as 30 dB, as well as low insertion losses −5 dB, making it compatible with industrial needs for device applications.

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Ferromagnetic nanowire-loaded membranes for microwave electronics

Cited by 92 publications

References 13 publications

Static and dynamic magnetic properties of densely packed magnetic nanowire arrays

Static and dynamic magnetic properties of densely packed magnetic nanowire arrays

On the behavior of Ni Magnetic Nanowires as studied by FMR and the effect of “blocking”.

Microwave circulator based on ferromagnetic nanowires in an alumina template

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