Systems in accordance with the present invention can include a tip contactable with a media, the media including a substrate and a plurality of cells disposed over the substrate, one or more of the cells being electrically isolated from the other of the cells by a material having insulating properties. One or more of the plurality of cells can include a phase change material. The media is either grounded or electrically connected with a voltage source such that when the tip is placed in contact with the media and a voltage is applied to the tip, a current is drawn through the cell over which the tip is arranged. The current is drawn through the isolated cell at least a portion of the phase change material within the cell beneath the tip is heated to a sufficient temperature such that the material become amorphous in structure. The current is then removed from the phase change material, which is quickly cooled to form an amorphous domain having a resistance representing a "1" (or a "0"). In another embodiment the one or more of the plurality of cells can include a polarity dependent material. In an embodiment, the one or more cells can have a sidewall structure that tapers along the depth of the cell so that the cell has a wider cross-section near where a tip contacts the media and a narrower cross-section near where the cell contacts one of the substrate and an underlayer.