The basic technology of magnetic data storage has been known since the late 19th century. The short version to explain how this works is explained that If small magnetizable particles on a substrate are influenced by a magnet or electromagnet they will arrange themselves in a north-south direction or in south-north direction depending on the current magnet orientation (in case of electromagnet orientation this depends on the current). The result is the two states of a bit (short for a binary digit), the state of zero and the state of one. Applying this physical property to a large number of bits gives devices such as hard disk drives the ability to store and retrieve data.
In order to make a storage device smaller and more efficient, hard disk drive manufacturers have spent much time and effort searching for new materials. The main problem encountered relates to the size. Once the magnetic area (sector) becomes small enough the laws of physics no longer apply and the quantum mechanical state comes into play.
Molecule-Based Magnets For Data Storage
Some years ago scientists began research of single-molecule magnets and magnetism of nanoparticles. For a long period of time molecules were considered non-magnetic materials, but this was likely based on a wrong assumption. The latest research shows that molecules can carry relatively large magnetic movement. These are the Single-molecule magnets or SMM. SMM are a class of metalorganic compounds, that show superparamagnetic behavior below a certain blocking temperature on the molecular scale. At this temperature range, SMMs exhibit magnetic hysteresis of purely molecular origin.
These molecules not only have the properties of magnets, they also have quantum properties which can be important for molecular data storage or for the purpose of the quantum computing. The nanometer-sized molecules consist of a fixed number of atoms, usually built for a specific function and therefore production can be relatively inexpensive. In addition to the electric charge of the electrons and the magnetic movement, or spin, SMMs can be used for non-volatile memory or even a quantum computer.
The ability of a single molecule to behave like a tiny magnet has seen a rapid growth in research over the past few years. SMMs represent the smallest possible magnetic devices and are a controllable, bottom-up approach to nanoscale magnetism.
Potential applications of SMMs include quantum computing, high-density information storage and magnetic refrigeration. A major problem scientist have had in the past when dealing with the molecules was the operational temperatures necessary, around -200°C. Recently scientists have developed a two molecule thick “sandwich” of cobalt and a material named “Zinkmethylphenylalenyl”. The newly developed sandwich runs at a relatively “warm” 20 degrees below zero.
This is a significant step towards the development of molecular data storage operational at room temperature.