Nanomechanical torque magnetometry of an individual aggregate of ∼350 nanoparticles

Firdous, Tayyaba; Vick, D.; Belov, M.; Sani, Fatemeh Fani; McDermott, A.; Losby, Joseph; Bazylinski, Dennis A.; Prozorov, Tanya; Potter, David K.; Freeman, M. R.

doi:10.1139/cjp-2014-0722

Cited by 4 publications

(12 citation statements)

References 29 publications

(1 reference statement)

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“…The high detection sensitivity of resonant nanomechanical torque sensors has allowed for minimally-invasive observations of magnetostatic interactions and hysteresis in a variety of magnetic materials including thin films [15], mesoscale confined geometries that are deposited [16] or epitaxially grown [17], and small aggregates of nanoparticles [18]. Going beyond the static limit, nanomechanical torque magnetometry has been extended to timescales allowing for detection of slow thermally-activated dynamics [12], AC susceptibility [17], and magnetic resonance [19,20].…”

mentioning

confidence: 99%

Nanocavity optomechanical torque magnetometry and radiofrequency susceptometry

Wu¹,

Wu²,

Firdous³

et al. 2016

Nature Nanotech

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Nanophotonic optomechanical devices allow observation of nanoscale vibrations with sensitivity that has dramatically advanced metrology of nanomechanical structures [1][2][3][4][5][6][7][8][9] and has the potential to impact studies of nanoscale physical systems in a similar manner [10,11]. Here we demonstrate this potential with a nanophotonic optomechanical torque magnetometer and radiofrequency (RF) magnetic susceptometer. Exquisite readout sensitivity provided by a nanocavity integrated within a torsional nanomechanical resonator enables observations of the unique net magnetization and RF-driven responses of single mesoscopic magnetic structures in ambient conditions. The magnetic moment resolution is sufficient for observation of Barkhausen steps in the magnetic hysteresis of a lithographically patterned permalloy island [12]. In addition, significantly enhanced RF susceptibility is found over narrow field ranges and attributed to thermally assisted driven hopping of a magnetic vortex core between neighboring pinning sites [13]. The on-chip magneto-susceptometer scheme offers a promising path to powerful integrated cavity optomechanical devices for quantitative characterization of magnetic micro-and nanosystems in science and technology.Torque magnetometry has seen recent resurgence owing to miniaturization of mechanical devices [14]. The high detection sensitivity of resonant nanomechanical torque sensors has allowed for minimally-invasive observations of magnetostatic interactions and hysteresis in a variety of magnetic materials including thin films [15], mesoscale confined geometries that are deposited [16] or epitaxially grown [17], and small aggregates of nanoparticles [18]. Going beyond the static limit, nanomechanical torque magnetometry has been extended to timescales allowing for detection of slow thermally-activated dynamics [12], AC susceptibility [17], and magnetic resonance [19,20].This powerful technique relies upon detection of the deflection of a mechanical element by angular momentum transfer originating from magnetic torques τ = µ 0 m×H, generated as the magnetic moments in the system, m, experience an orthogonally-directed component of the applied magnetic field, H. So far, improvements to torque magnetometers have been driven primarily by enhancements to the response of nanomechanical resonators resulting from their low mass and high mechanical quality factor (Q m ). Readout of magnetically driven motion has involved detection through free-space optical interferometric methods with very low optical quality factor (Q o ≈ 1) Fabry-Perot cavities formed between the nanomechanical resonator its supporting substrate [16]. However, as device dimensions scale down, and the number of magnetic spins become too small or the dynamics too fast, the mechanical deflections become more difficult to detect. Migration to a more sensitive readout scheme is essential. The integration of a nanoscale optical cavity offers a natural path for improvement. Nanocavity-optomechanical devices enhance mechanarXiv:...

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mentioning

confidence: 99%

Nanocavity optomechanical torque magnetometry and radiofrequency susceptometry

Wu¹,

Wu²,

Firdous³

et al. 2016

Nature Nanotech

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“…The nanoparticles used in [3] were stable single domain nanoparticles (55 nm in size) having a large magnetic moment. It would be interesting to fabricate devices with higher sensitivity that can also measure magnetic nanoparticles with a lower magnetic moment and smaller size.…”

Section: Patterning Nanoparticles Of the Device Shape (Negative Resist)mentioning

confidence: 99%

“…These resonance modes were measured before cleaning with the FIB. The devices were comparatively in the high frequency range as compared to the nanomechanical devices in the silicon nitride membrane [3]. The increasing length of the torsional rod from device B5 to device B9 changes the flexural and torsional resonance modes to the lower frequency.…”

Section: Nanomechanical Torque Magnetometry Of Nanoparticles On the Dmentioning

confidence: 99%

“…The measurement of the magnetic properties of a small-scale assembly of nanoparticles has been a challenge. The magnetic properties of~350 magnetite nanoparticles by nanomechanical torque magnetometry, assembled by a Nano eNabler, was presented in [3]. However, information was lost due to the random assembly of the nanoparticles on the device, and the magnetic properties averaged out along any given axis.…”

Section: Introductionmentioning

confidence: 99%

“…The top-down process includes making the devices and controlling the shape of the nanostructures, whereas the bottom-up process includes the self-assembly of nanoparticles. The SOI devices have advantages of high sensitivity and good resonance modes, along with the elimination of membrane modes as in the case of devices made in a silicon nitride membrane [3]. The difficulties in device fabrication in a silicon nitride membrane is represented in the Supplementary Materials.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Assembling Magnetic Nanoparticles on Nanomechanical Resonators for Torque Magnetometry

Firdous

Potter

2020

IJMS

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We report a highly compliant process for patterning nanoparticle arrays on micro- and nanomechanical devices. The distinctive step involves the single layer self-assembled nanoparticles on top of released nanomechanical devices. We demonstrate the process by fabricating sizable arrays of nanomechanical devices on silicon-on-insulator substrates, acting as nanomechanical torque magnetometers. Later, the nanoparticles were self-assembled in geometrical shapes on top of the devices by a unique combination of top-down and bottom-up methods. The self-assembled array of nanoparticles successfully showed a magnetic torque signal by magnetic actuation of the magnetometer. This patterning process can be generalized for any shape and for a wide range of nanoparticles on the nanomechanical resonators.

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Membrane-based torque magnetometer: Enhanced sensitivity by optical readout of the membrane displacement

Blankenhorn

Heintze

Slota

et al. 2017

Review of Scientific Instruments

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The design and realization of a torque magnetometer is reported that reads the deflection of a membrane by optical interferometry. The compact instrument allows for low-temperature measurements of tiny crystals less than a microgram with a significant improvement in sensitivity, signal-to-noise ratio as well as data acquisition time compared with conventional magnetometry and offers an enormous potential for further improvements and future applications in different fields. Magnetic measurements on single-molecule magnets demonstrate the applicability of the membrane-based torque magnetometer.

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Nanomechanical torque magnetometry of an individual aggregate of ∼350 nanoparticles

Cited by 4 publications

References 29 publications

Nanocavity optomechanical torque magnetometry and radiofrequency susceptometry

Nanocavity optomechanical torque magnetometry and radiofrequency susceptometry

Assembling Magnetic Nanoparticles on Nanomechanical Resonators for Torque Magnetometry

Membrane-based torque magnetometer: Enhanced sensitivity by optical readout of the membrane displacement

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