This is interesting although truth is from reading between the lines it may be a long time before any drives based on this technology, or any other new technology, reach the market. Another problem we're already seeing from ever higher areal densities is lower reliability. It seems the failure rate of today's drives is an order of magnitude higher than I remember in the past. Given the smaller bits, lower flying heights of the head, and so forth, this really doesn't surprise me. I'm at the point I really don't even want to buy new hard drives because of this. I'm half ready to wait until SSDs drop in price to something reasonable.
I've already said a few years ago magnetic storage will like peak at a few terabytes, and then be supplanted by solid-state. We just need to make SSD cost competitive with magnetic disks. SSD is inherently way more reliable and scaleable than magnetic disks. I would imagine once you can't reliably shrink the size of storage cells any more, then you could simply stack chips inside a single package for greater capacity. IMO, all this will happen probably before any new technology to drastically increase magnetic disks is viable. The magnetic disk lived a long and useful life. Much like the incandescent light bulb, or internal combustion engine, that time is almost past because something better is coming along. Magnetic hard drives are the least reliable and slowest component of modern PCs by far. The sooner they can be cost-effectively replaced by SSDs, the better.