Posted on 10/15/2009 2:51:38 PM PDT by Free ThinkerNY
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.
(Excerpt) Read more at timesonline.co.uk ...
They’re not real monopoles. What the article describes is a technique by which a physicist or engineer can decide where exactly an object’s north and south poles should be. You can move them around over the surface of the object, but ultimately they still always come in pairs and there’s always contiguous spin alignment between them.
It’s a little bit like if I made a necklace made of bar magnets and claimed I had invented a monopole because I can hold up the north end of the necklace while leaving the south end dangling somewhere out of sight.
How magnetricity works in spin ice Dy2Ti2O7: (a) In zero field, magnetic charges occur as bound pairs, but some dissociate to give a fluctuating magnetic moment (green arrow). (b) The field energy competes with the Coulomb potential to lower the activation barrier to dissociation. (c) Applying a transverse field causes dissociation as charges are accelerated by the field. (d) In the applied field, these charges remain dissociated while more bound pairs form to restore equilibrium. Magnetic moment fluctuations due to free charges produce local fields that are detected by implanted muons (+).
This is lame then.
If you picture the spin ice as a closed system, then they’re just as much true monopoles as electrons are true negative electrical poles in our universe and protons true positive poles.
The idea that the north and south poles of a magnet can exist independently was first proposed by Paul Dirac, a physicist, in 1931.
Does Van Vleck have to return *his* Nobel? I once read that he was *adamant* that there could be no magnetic monopoles...
(Snarks, do you know aught of this story?)
Cheers!
The same can be said if you picture my hypothetical necklace of bar magnets as a closed system. All I gotta do is flip a segment of the necklace, and, presto! Monopole!
b000ring.
What you're left with when her attraction to you does not match your attraction to her.
Taggus Linus H1N1... weird.
;’)
A crystal lattice’s quirky behavior is not an elementary monopole. This and similar phenomena are done with lattice formations as a sort of trick. At low enough temperatures geometric frustration prevents the full superdiamagnetism effect from taking hold. It’s novel and potentially very useful but not related to Dirac’s elementary particle proposition.
It's related insofar as it models or mimics the behavior of magnetic monopoles. Certainly it is no step towards the discovery of elementary magnetic monopoles, or anything of that sort.
The existence of a Dirac monopole would revolutionize much of our physical theoretical understanding. This is not it.
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