Droplet manipulation is kindling great interest in several fields, including technological applications and basic studies in dynamic systems. The Lab-on-a-chip and microfluidics community is particularly interested in the precise manipulation of small volumes of fluids, droplet microfluidics. A piece of research conducted by the UPV/EHU's Microfluidics Cluster  has found that a superparamagnetic ring forms spontaneously around a water droplet when an oil-based ferrofluid is in contact with the droplet under the influence of a magnetic field and varies according to the strength of the magnetic field applied.