Room temperature scanning Hall probe microscopy of localized magnetic field fluctuations on the surfaces of magnetic recording media, permanent magnets and crystalline garnet films in external bias fields

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

doi:10.1016/s0304-8853(01)00987-8

Cited by 20 publications

(14 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since Martin and Wickramasinghe 1 first investigated imaging of materials using a magnetic force microscope (MFMs 2,3 ), three other methods have been developed. These methods use a scanning superconductivity quantum interface device (SQUID), 4–6 an scanning magnetoresistance microscope (SMRM) 7,8 or an scanning Hall probe microscope (SHPM) 9–14 . Only researchers using SHPMs gave information about temperature (4–90 K in Ref.…”

Section: Methodsmentioning

confidence: 99%

“…These methods use a scanning superconductivity quantum interface device (SQUID), 4-6 an scanning magnetoresistance microscope (SMRM) 7,8 or an scanning Hall probe microscope (SHPM). [9][10][11][12][13][14] Only researchers using SHPMs gave information about temperature (4-90 K in Ref. [10]; 77 K, 110 K and 140 K in Ref.…”

Section: Scanning Hall Probe Microscope (Shpm)mentioning

confidence: 99%

See 1 more Smart Citation

Changes in magnetic flux density around fatigue crack tips

Kida

Tanabe

Okano

2009

Fatigue Fract Eng Mat Struct

View full text Add to dashboard Cite

A B S T R A C T Fatigue failure of steel occurs when small cracks form in a component and then continue to grow to a size large enough to cause failure. In order to understand the strength of steel components, it is important to find the cracks, which eventually grow to cause failures. However, at present, it is not easy to distinguish, in the early stages of growth, the cracks that will grow fast and cause failure. We hypothesized that it may be possible to distinguish them by comparing changes in the magnetic flux density around the tips of those cracks that grew to failure. In order to measure these changes in magnetic flux density, we developed a scanning Hall probe microscope and observed the fatigue cracks growing from artificial slits in soft bearing steels. Note that we did not magnetize the specimens artificially but succeeded to measure the changes in magnetic flux density during the fatigue tests. We also compared the changes in magnetic flux density around crack tips, which grew under different loads, and found that there is a strong correlation between the magnetic flux density, crack growth and stress intensity factors. In order to understand this, we looked into the relation between stress field, residual strain and magnetic flux density, and concluded that the changes in magnetic flux density are caused not only by the residual strain occurring around the crack tips but also by the increase in the elastic stress.Keywords bearing steel; fatigue crack growth; magnetic flux density; non-destructive method; scanning Hall-probe microscope; stress intensity factor. N O M E N C L A T U R Ea = crack length B = magnetic flux density Bn = normalized value of magnetic flux density FWHM = full width at half maximum K = stress intensity factor P = load W = height of bar specimen Ya = y-coordinate of apex of the magnetic flux density distribution Yb = y-coordinate where the values of magnetic flux density distributions become the same as the values when their distribution curves converge.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Scanning Hall Probe Microscope (Shpm)mentioning

confidence: 99%

Changes in magnetic flux density around fatigue crack tips

Kida

Tanabe

Okano

2009

Fatigue Fract Eng Mat Struct

View full text Add to dashboard Cite

show abstract

“…These methods use a SQUID (scanning superconductivity quantum interface device) 4,5,6 , an SMRM (scanning magnetoresistance microscope) 7,8 or an SHPM (scanning Hall probe microscope) 9,10,11,12,13,14 . Recently Mori et al 15 used Hall probe to study stress fields.…”

Section: Introductionmentioning

confidence: 99%

Changes in magnetic flux density around fatigue crack tips of carbon tool steels

et al. 2009

View full text Add to dashboard Cite

Fatigue failure of steel occurs when small cracks form in a component and then continue to grow to a size large enough to cause failure. In order to understand the strength of steel components it is important to find the cracks which eventually grow to cause failures. However, at present, it is not easy to distinguish, in the early stages of growth, the cracks which will grow fast and cause failure. We hypothesized that it may be possible to distinguish them by comparing changes in the magnetic flux density around the tips of those cracks that grew large enough to cause failure. In order to measure these changes in magnetic flux density, we developed a scanning Hall probe microscope and observed the fatigue cracks growing from artificial slits in carbon tool steels (JIS SKS93). We also compared the changes in magnetic flux density around crack tips which grew under different loads and found that there is a strong correlation between the magnetic flux density, crack growth and stress intensity factors. In order to understand this relation, we measured the changes in the magnetic flux density and residual tensile stress by using an X-ray system, and found that the magnetic flux density changes not only in the plastic deformation area but also in the area of elastic stress field with increased stress.

show abstract

“…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

View full text Add to dashboard Cite

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.

show abstract

Room temperature scanning Hall probe microscopy of localized magnetic field fluctuations on the surfaces of magnetic recording media, permanent magnets and crystalline garnet films in external bias fields

Cited by 20 publications

References 4 publications

Changes in magnetic flux density around fatigue crack tips

Changes in magnetic flux density around fatigue crack tips

Changes in magnetic flux density around fatigue crack tips of carbon tool steels

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

Contact Info

Product

Resources

About