Moving monopoles detected
The search for magnetic monopoles - isolated magnetic charges that can move freely, similarly to electrical charges - has long been considered one of the principal challenges of modern physics in the field of electromagnetism. A study published in Nature Physics reports the detection of moving monopoles at room temperature in an assembly of nanomagnets, in research carrired out by a team including Arantxa Fraile Rodríguez from the UB's Department of Fundamental Physics, who took part in the project during a temporary stay at the Paul Scherrer Institut (Suiza).
The search for magnetic monopoles - isolated magnetic charges that can move freely, similarly to electrical charges - has long been considered one of the principal challenges of modern physics in the field of electromagnetism. A study published in Nature Physics reports the detection of moving monopoles at room temperature in an assembly of nanomagnets, in research carrired out by a team including Arantxa Fraile Rodríguez from the UB's Department of Fundamental Physics, who took part in the project during a temporary stay at the Paul Scherrer Institut (Suiza).
Magnetic poles always appear in pairs, meaning that a magnet is an elementary component with both a north and a south pole. Therefore, dividing a magnet in two does not divide the poles themselves but in fact creates two new magnets, each of which will have its own north and south poles. In 1931, the physicist Paul Dirac concluded that these monopole pairs can be separated provided that a connection is maintained between them that transports the magnetic flux, which became known as the "Dirac String".
"In our study we were able to generate monopoles in an artificial assembly of nanomagnets and observe their movement at room temperature. When we inverted the magnetization we found that two oppositely-charged monopoles remained connected by a one-dimensional line of magnets, where the north pole of each magnet is next to the south pole of its neighbour, and so form the Dirac string", explains Fraile.