If the title is catchy, the idea of Toshiba is to develop a magnetic head capable of writing – and reading – data on layers of substrates stacked on the same platter by using microwaves. This could actually be considered as 3D reading/writing on magnetic disks!
The MAMR technology (Microwave Assisted Magnetic Recording) was announced and demonstrated in July 2015 during the 20th International Conference on Magnetism (ICM) in Barcelona. It is reminiscent of the principle of reading/writing on multilayer optical discs used on DVD9 and other Blu-Ray discs, and also some variations of optomagnetic discs released in recent decades. But any similarity ends there: there is no optics involved in the technology that Toshiba intends to develop. Everything here concerns magnetism and electromagnetism.
Technology improving all the time
It must be realised that we are at the level of Research and Development and not yet of a technology that may be available in two or three years. In principle, since it is 3D, this means that multiple separate data can be recorded at a single place of the drive; the number of bits will depend on the number of stacked layers. In practice, the procedure consists in resonating only one layer at a given moment at a specific location, using a certain wavelength of the microwave transmitter which is adjacent to the magnetic head.
Upon activation of the right wavelength, it is the data of the layer 1, 2 or other that will be in a state capable of being read or written. It should be remembered that writing is generally more complicated. Especially considering stacked layers! Because it takes a significant input of energy to reverse the polarity of the medium. However, the addition of the frequency of the microwaves that cause the resonance of the layer is no more energy-consuming than if the layer was on the first stacking level, or perhaps even less. Thus, it is precisely the ferromagnetic resonance frequency of each layer which is specific.
Toshiba at the Forefront of Research
To establish Toshiba’s level in terms of research, emphasis is currently placed on the precision of the element causing the microwave resonance so that it is able to write increasingly fine bits on the support.
With its MAMR technology, Toshiba expects to multiply storage density of the drive surface by 10, compared to the currently existing technology. In addition, Toshiba sees its technology as more interesting than the HAMR (Heat Assisted Magnetic Recording) technology used notably by Seagate because it does not pose certain thermal demagnetisation problems to the support over time.
Diagram credit: Forbes