7,439 research outputs found
A Novel Bar-Shaped Magnetic Shielding for Magnetoresistive Sensors in Current Measurement on Printed Circuit Boards
Session PF: Materials for Applications, abstract no. PF-02This paper presents the study of a novel bar-shaped magnetic shielding for magnetoresistive (MR) sensors in current measurement on printed circuit boards (PCB). The main physical principles of the shielding effect were studied by using the analytical model of magnetic flux concentration. Finite element analysis (FEA) simulations were used to simulate the shielding effects with changing geometrical parameters of the bar-shaped magnetic shielding. The dependences of the shielding effect on the parameters of length, width and thickness were analyzed. It shows that these parameters are critical for designing magnetic shielding. This new concept of magnetic shielding for MR sensors in current measurement on PCB was experimentally tested and verified in a laboratory setup. The experimental results verify the feasibility and effect of this novel magnetic shielding for MR sensors.published_or_final_versio
Improved ferrous shielding for flat cables
To improve shielding of flat multicore cables, a thin, seamless ferrous shield around all cores optimizes low frequency magnetic shielding. Such shielding is covered with an ultrathin seamless coat of highly conductive nonferrous material
Magnetic shielding and exotic spin-dependent interactions
Experiments searching for exotic spin-dependent interactions typically employ
magnetic shielding between the source of the exotic field and the interrogated
spins. We explore the question of what effect magnetic shielding has on
detectable signals induced by exotic fields. Our general conclusion is that for
common experimental geometries and conditions, magnetic shields should not
significantly reduce sensitivity to exotic spin-dependent interactions,
especially when the technique of comagnetometry is used. However, exotic fields
that couple to electron spin can induce magnetic fields in the interior of
shields made of a soft ferro- or ferrimagnetic material. This induced magnetic
field must be taken into account in the interpretation of experiments searching
for new spin-dependent interactions and raises the possibility of using a flux
concentrator inside magnetic shields to amplify exotic spin-dependent signals.Comment: 8 pages, 5 figure
Improvement of critical current in MgB2/Fe wires by a ferromagnetic sheath
Transport critical current (Ic) was measured for Fe-sheathed MgB2 round
wires. A critical current density of 5.3 x 10^4 A/cm^2 was obtained at 32K.
Strong magnetic shielding by the iron sheath was observed, resulting in a
decrease in Ic by only 15% in a field of 0.6T at 32K. In addition to shielding,
interaction between the iron sheath and the superconductor resulted in a
constant Ic between 0.2 and 0.6T. This was well beyond the maximum field for
effective shielding of 0.2T. This effect can be used to substantially improve
the field performance of MgB2/Fe wires at fields at least 3 times higher than
the range allowed by mere magnetic shielding by the iron sheath. The dependence
of Ic on the angle between field and current showed that the transport current
does not flow straight across the wire, but meanders between the grains
Local magnetic measurements in magnetic circuits with highly nonuniform electromagnetic fields
In this paper, local magnetic measurements are carried out in magnetic circuits with highly non uniform electromagnetic field patterns, including excitation winding and/or air gaps, as in
the case of rotating electrical machines. The effect of sensor choice, sensor noise sensitivity, electromagnetic field nonlinearity, and magnetic shielding are investigated. Moreover, the validity of the local magnetic measurements is confirmed by numerical models
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