Magnetics Business & Technology - July/August 2022 - 13

FEATURE ARTICLE
lowing its transformational, game changing properties and benefits
to be harnessed. "
Comprising a monolayer carbon lattice with strong atomic bonds,
graphene's key attributes include high levels of mechanical stability
(having tensile strength 200x that of steel), outstanding electrical
conductivity (an order of magnitude higher than copper) plus extraordinary
thermal conductivity (currently the highest of any known
material), explains Thomas, noting the importance of the company's
approach to graphene fabrication which allowed it to leverage the
attributes to commercial scope beginning with magnetic sensors.
A stalwart of electronic system design, the Hall-Effect sensor serves
a pivotal role in many applications particularly in the automotive industry.
Basically, a Hall-Effect sensor is a transducer which varies
its output voltage in response to a magnetic field. They sensors are
used for proximity switching, positioning, speed detection and current
sensing.
Technology explained
Something that has always proved problematic with conventional
Hall-Effect sensors, explains Thomas, is that the sensing element
is three-dimensional. Its depth can lead to false measurement signals
being produced that emanate from the in-plane magnetic field
component, rather than the perpendicular one; referred to as the
planar Hall Effect. Such false signals interfere with the real signals
and give the impression that there are additional magnetic poles
present.
Referred to as 'pseudo-multipoles', these will mean that measurement
accuracy is impacted upon. Though the real signals and the
false signals can be separated from one another using additional
circuitry, this will add significantly to system complexity and power
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Getting production to commercial levels, however, has been elusive.
Through the process that the Paragraf engineering team has
developed, it is possible to produce single-atom thick layers directly
onto crystalline semiconductor wafer substrates. The sensors have
set new performance benchmarks, says Thomas. " As the active
sensing element in each device is comprised of a single atom-thick
graphene monolayer, the influence of the planar Hall Effect has
been totally eliminated. These devices deliver 30x greater sensitivity
than the conventional silicon-based options and have better
operational stability. "
One of the company's next endeavors is development of a graphene-based
biosensor that's targeted at transforming clinical point
of care in the medical industry. For more info, see www.paragraf.
com and previous articles in Magnetics Magazine.
consumption, limit the operational temperature range and push up
cost. As graphene is two-dimensional, consisting of just an atomthick
monolayer of carbon, it is not susceptible to the in-plane field
component and it displays a very low thermal noise floor. Hence
using it in magnetic field measurement enables significantly more
accurate results to be derived.
SALES@MEDA.COM
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FAX: 703.996.8770
July/August 2022 * Magnetics Business & Technology 13
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Magnetics Business & Technology - July/August 2022

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