We tend to associate magnetism to iron or similar metallic materials. As a matter of fact magnetism occurs any time there is a prevalence in the orientation of each atom magnetic field into a single direction. Normally, atoms have their magnetic field oriented at random and the net result is a zero magnetic field as measured around the object.
Magnet properties turn out to be useful in several applications, electrical motor just mention the most obvious application, but they are also important as a way to store bits (magnetic memories, like the one you have in your hard drive -unless you are a rich guy that has invested his money in buying an SSD drive where bits are stored in transistors).
Graphene is a one atom layer thick material, with all its carbon atoms nicely arranged in hexagonal rings. It has many nice properties but magnetisms is not one of them. Researchers have tried to create a magnetised graphene by inserting some "doping" atoms (a quite common approach in the semiconductor and optoelectronics industry) but so far this has not been successful because the induction of magnetic properties in the graphene layer disrupted some of its other properties.
Now researchers at the UC Riverside have found a way to keep all the nice properties of graphene and add the magnetisation on top of them. They managed to do the trick by layering the graphene over a yttrium iron garnet that provided the desired magnetic properties without interfere with the electrical properties of graphene. Remember that magnetism is another aspect of the electrical field (Maxwell equations...) and the interaction of the two give rise to interesting quantum effects that in turns can lead to new devices, as we are reaching the size where quantum effects are becoming visible. An example is the use of graphene in spintronics for creating ultra dense storage devices.
The path towards higher storage density has not reached the end of the line, some are saying we have just began, and discoveries like this one are a point in case!