US boffins working on nano-tech magneto-electronic storage devices
A US scientist has been conducting research that it is hoped will lead to the creation of nano-tech magneto-electronic storage devices on the scale of billionths of a metre.
In the world of electronic and magnetic devices, the goal is to get smaller, explained Yimei Zhu, a senior scientist at the US Department of Energy's Brookhaven National Laboratory.
"The smaller space one bit of information can occupy, the more data you can get into a device and the faster it can operate," he said.
Zhu's group has fabricated patterned magnetic films by depositing magnetic materials such as Permalloy and cobalt in patterns of dots, squares or ellipses across a surface of non-magnetic substrates such as carbon or silicon nitride.
As each dot measures about 100 nanometres across, these materials could serve as building blocks for new nano-scale magneto-electronic devices and data storage media.
"For digital communication and data storage applications, such as magnetic recording media, you need two stable states to encode the 'ones' and 'zeros' of digital information," Zhu said.
In his array of magnetic dots, the two states are the two distinct spin orientations, or polarities, of the dots' internal magnetic fields.
Using a field-emission transmission electron microscope equipped with a custom-made objective lens, the only one like it in the world, Zhu's group can probe the magnetic properties (including spin orientation) of each dot.
This allows them to map how the spins 'flip' in response to an external magnetic field, or other variables such as temperature, environment and crystal defects.
The technique uses an extremely coherent source of electrons to produce images with unprecedented quality at high resolution in which the amplitude and direction of local magnetisation can be clearly visualised.
"What we are looking for is two very stable states with a well-defined switching mechanism," Zhu explained.
Such a medium could be encoded with digital data by switching the spins from 'up' to 'down', or clockwise to counterclockwise, at will, without interference from other variables.
"In order to make these materials into useful, practical magnetic building blocks we really have to understand this switching, or reversal, mechanism," Zhu said.
The precise measurements allow the scientists to compare experimental observations with calculations to validate various theoretical models.
Once the researchers understand the mechanism, they may be able to scale the materials down even smaller, perhaps to the molecular scale.
A US scientist has been conducting research that it is hoped will lead to the creation of nano-tech magneto-electronic storage devices on the scale of billionths of a metre.
In the world of electronic and magnetic devices, the goal is to get smaller, explained Yimei Zhu, a senior scientist at the US Department of Energy's Brookhaven National Laboratory.
"The smaller space one bit of information can occupy, the more data you can get into a device and the faster it can operate," he said.
Zhu's group has fabricated patterned magnetic films by depositing magnetic materials such as Permalloy and cobalt in patterns of dots, squares or ellipses across a surface of non-magnetic substrates such as carbon or silicon nitride.
As each dot measures about 100 nanometres across, these materials could serve as building blocks for new nano-scale magneto-electronic devices and data storage media.
"For digital communication and data storage applications, such as magnetic recording media, you need two stable states to encode the 'ones' and 'zeros' of digital information," Zhu said.
In his array of magnetic dots, the two states are the two distinct spin orientations, or polarities, of the dots' internal magnetic fields.
Using a field-emission transmission electron microscope equipped with a custom-made objective lens, the only one like it in the world, Zhu's group can probe the magnetic properties (including spin orientation) of each dot.
This allows them to map how the spins 'flip' in response to an external magnetic field, or other variables such as temperature, environment and crystal defects.
The technique uses an extremely coherent source of electrons to produce images with unprecedented quality at high resolution in which the amplitude and direction of local magnetisation can be clearly visualised.
"What we are looking for is two very stable states with a well-defined switching mechanism," Zhu explained.
Such a medium could be encoded with digital data by switching the spins from 'up' to 'down', or clockwise to counterclockwise, at will, without interference from other variables.
"In order to make these materials into useful, practical magnetic building blocks we really have to understand this switching, or reversal, mechanism," Zhu said.
The precise measurements allow the scientists to compare experimental observations with calculations to validate various theoretical models.
Once the researchers understand the mechanism, they may be able to scale the materials down even smaller, perhaps to the molecular scale.
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