From The London Times
Discovery of ‘magnetricity’ marks important advance in physics
Hannah Devlin
Scientists have generated a magnetic version of electricity, which they have called magnetricity.
The discovery marks an important advance in theoretical physics. The existence of magnetic “charges” has been predicted for nearly 70 years but has never been observed in practice.
The study was led by Professor Steve Bramwell, of the London Centre for Nanotechnology. He said: “It is not often in the field of physics you get the chance to ask, ‘How do you measure something?’, and then go on to prove a theory unequivocally. This is a very important step to establish that magnetic charge can flow like electric charge.”
While electrical current is carried by electrons, magnetricity is based on atomic-sized “north” and “south” charges that flow through materials when placed in a magnetic field.
The idea that the north and south poles of a magnet can exist independently was first proposed by Paul Dirac, a physicist, in 1931.
However, in everyday life poles always seem to occur in north-south pairs: no matter how many times you break a bar magnet in half, it will always have a north end and a south end.
Dredging through the fallout from collisions in particle accelerators and straining to pick up cosmic rays from the early universe also failed to turn up elementary particles that have just one pole.
Now research, published today in the journal Nature, shows that “north” and “south” charges can be isolated and rove around independently in a crystalline material called dysprosium titanate. The crystals possess two unusual magnetic properties stemming from the way the atoms are arranged.
Each atom in the crystal acts as a little bar magnet, complete with a north and a south. But the geometrical layout of the atoms means that the norths and souths are never able to align in a satisfactory way and so the magnets continually flip up and down trying to find a stable position.
“It’s like having a sea of bar magnets. If you flip one then the next one will flip around as well,” said Dr Sean Glibin, of the ISIS particle accelerator at the Rutherford Appleton Laboratory near Oxford.
The second unusual property is that at regular intervals on the lattice the magnetic fields of individual atoms add up to produce essentially isolated north or south charges.
The combination of these two properties means that when the individual atoms flip the norths and souths move along the lattice. Without applying a magnetic field, the charges move around at random. But when a magnetic field is applied, the researchers showed that the charges flow through the crystal in exactly the same way that electrons flow through metallic conductors.
It is unlikely to become an immediate replacement for electricity because the crystals have to be cooled to below minus 272.15C — just above absolute zero — to be conducting. However, Professor Bramwell said that the discovery could have important applications in the emerging field of nanocomputing.
Discovery of ‘magnetricity’ marks important advance in physics
Hannah Devlin
Scientists have generated a magnetic version of electricity, which they have called magnetricity.
The discovery marks an important advance in theoretical physics. The existence of magnetic “charges” has been predicted for nearly 70 years but has never been observed in practice.
The study was led by Professor Steve Bramwell, of the London Centre for Nanotechnology. He said: “It is not often in the field of physics you get the chance to ask, ‘How do you measure something?’, and then go on to prove a theory unequivocally. This is a very important step to establish that magnetic charge can flow like electric charge.”
While electrical current is carried by electrons, magnetricity is based on atomic-sized “north” and “south” charges that flow through materials when placed in a magnetic field.
The idea that the north and south poles of a magnet can exist independently was first proposed by Paul Dirac, a physicist, in 1931.
However, in everyday life poles always seem to occur in north-south pairs: no matter how many times you break a bar magnet in half, it will always have a north end and a south end.
Dredging through the fallout from collisions in particle accelerators and straining to pick up cosmic rays from the early universe also failed to turn up elementary particles that have just one pole.
Now research, published today in the journal Nature, shows that “north” and “south” charges can be isolated and rove around independently in a crystalline material called dysprosium titanate. The crystals possess two unusual magnetic properties stemming from the way the atoms are arranged.
Each atom in the crystal acts as a little bar magnet, complete with a north and a south. But the geometrical layout of the atoms means that the norths and souths are never able to align in a satisfactory way and so the magnets continually flip up and down trying to find a stable position.
“It’s like having a sea of bar magnets. If you flip one then the next one will flip around as well,” said Dr Sean Glibin, of the ISIS particle accelerator at the Rutherford Appleton Laboratory near Oxford.
The second unusual property is that at regular intervals on the lattice the magnetic fields of individual atoms add up to produce essentially isolated north or south charges.
The combination of these two properties means that when the individual atoms flip the norths and souths move along the lattice. Without applying a magnetic field, the charges move around at random. But when a magnetic field is applied, the researchers showed that the charges flow through the crystal in exactly the same way that electrons flow through metallic conductors.
It is unlikely to become an immediate replacement for electricity because the crystals have to be cooled to below minus 272.15C — just above absolute zero — to be conducting. However, Professor Bramwell said that the discovery could have important applications in the emerging field of nanocomputing.
No comments:
Post a Comment