Hyderabad, Apr 11: Physicists have magnetically levitated solid objects - including gold, platinum and diamond, in cold oxygen gas for the first time, says a report in the science journal 'Nature'.
Laurence Eaves and colleagues at Nottingham University were also able to move the floating objects by adjusting the strength of the applied magnetic field. They believe that the effect could find applications in mineral seperation technology.


Magnetic levitation occurs when the force on a 'diamagnetic' object is strong enough to balance the weight of the object itself.



If the object is immersed in a 'paramagnetic' fluid, such as gaseous oxygen, the levitator can be enhanced by the effect of buoyancy caused by the 'magneto-Archimedes' effect. The levitation force per unit volume of the object depends on the vertical magnetic field gradient in the vessel.


Liquid oxygen can provide even greater buoyancy - enough to float dense diamagnetic objects at relatively low magnetic field strengths. Each object floats at the point at which the local magneto-Archimedes force balances its weight, and the position of the object can be adjusted by changing the magnetic field strength. Bureau Report