Room temperature magnetic imaging of magnetic storage media and garnet epilayers in the presence of external magnetic fields using a sub-micron GaAs SHPM

Sandhu, Adarsh; Masuda, Hiroshi; Oral, Ahmet; Bending, S. J.

doi:10.1016/s0022-0248(01)00925-3

Cited by 17 publications

(11 citation statements)

References 19 publications

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“…attached to a flexible, polyimide cantilever. During our experiments, the polyimide cantilever was attached to a base plate that was fixed by screws onto a specially designed holder of our room temperature SHPM system [3]. Gold electrode pads were evaporated onto the polyimide cantilever to bond gold wires from the edge of the Hall probe to the cantilever.…”

Section: A Fabrication Of Algaas/ingaas Hall Probesmentioning

confidence: 99%

Contact Mode Scanning Hall Probe Microscopy

2008

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Scanning Hall probe microscopy (SHPM) is an established method for monitoring localized magnetic fields at the surfaces of ferromagnetic materials and magnetic media, as well as vortices in superconductors. Magnetic imaging measurements are usually made using Hall sensors with integrated scanning tunneling microscope tips (STM-tips). Hall probes are fixed to piezoelectric tubes and lowered to the sample surface until a tunneling current is detected, when feedback circuitry takes over to maintain the probe-sample separation and prevent damage to the device. However, Hall probes with STM-tips have limitations that include measurements requiring conducting sample surfaces and complicated electronics to monitor the tunneling current. Hall probe microscopy could be made more robust and offer improved magnetic sensitivity and spatial resolution by making measurements with the Hall probe in actual contact with sample surfaces without the use of STM tips and piezoelectric actuators. Here, we describe the development of a contact mode SHPM system (CM-SHPM), where the Hall probe was attached to a flexible cantilever and the probe-sample separation monitored using a simple strain gauge integrated onto the cantilever. The CM-SHPM offers a simple and highly reliable means of magnetic imaging of nonconducting samples over large areas and wide temperature ranges.Index Terms-Ferromagnetic materials, Hall sensors, magnetic domains, scanning Hall probe microscopy (SHPM).

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Section: A Fabrication Of Algaas/ingaas Hall Probesmentioning

confidence: 99%

Contact Mode Scanning Hall Probe Microscopy

2008

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“…Scanning Hall probe microscopy (SHPM) has been shown to be a valuable tool for the direct and quantitative method for magnetic imaging of localized surface magnetic fluctuations of superconductors and ferromagnetic materials [1][2][3]. A key element of a SHPM system is the magnetic field sensor or Hall probe (HP).…”

Section: Introductionmentioning

confidence: 99%

“…Thus selection of the material for fabricating the HP is very important in order to obtain high spatial resolution and high magnetic sensitivity. We have previously reported on the use of $1 lm 2 GaAs/AlGaAs 2DEG heterostructure (GaAs-2DEG) Hall-effect sensors as HPs for room temperature scanning Hall probe microscope (RT-SHPM) [3][4][5][6][7]. In spite of their excellent room temperature magnetic sensitivity, the GaAs-2DEG HPs are impractical for high spatial resolution RT-SHPM measurements because their performance is severely degraded for dimensions below $1.0 lm 2 due to surface depletion effects that limit the maximum drive current (I max ) and consequently the magnetic sensitivity.…”

Section: Introductionmentioning

confidence: 99%

Nano and micro Hall-effect sensors for room-temperature scanning hall probe microscopy

Sandhu¹

2004

Microelectronic Engineering

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GaAs/AlGaAs two-dimensional electron gas (GaAs-2DEG) Hall probes are impractical for sub-micron roomtemperature scanning Hall microscopy (RT-SHPM), due to surface depletion effects that limit the Hall driving current and magnetic sensitivity (B min ). Nano and micro Hall-effect sensors were fabricated using Bi and InSb thin films and shown to be practical alternatives to GaAs-2DEG probes for high resolution RT-SHPM. The GaAs-2DEG and InSb probes were fabricated using photolithography and the Bi probes by optical and focused ion beam lithography. Surface depletion effects limited the minimum feature size of GaAs-2DEG probes to $1.5 lm 2 with a maximum drive current I max of $3 lA and B min $ 0:2 G/ ffiffiffiffiffiffi ffi Hz p . The B min of 1.5 lm 2 InSb Hall probes was 6 Â 10 À3 G/ ffiffiffiffiffiffi ffi Hz p at I max of 100 lA. Further, 200 nm Â 200 nm Bi probes yielded good RT-SHPM images of garnet films, with I max and sensitivity of 40 lA and $0.80 G/ ffiffiffiffiffiffi ffi Hz p , respectively.

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“…There are limited studies on the magnetic effects in the recording data at the transition or the edges of every data bit, which has the physical characteristics of either a nearperpendicular north magnetic pole or a south magnetic pole as shown in Fig. 1 [7].…”

Section: Introductionmentioning

confidence: 99%