Page 499 - AWSAR 2.0

shows various conformations upon irradiation with ultraviolet (UV) light (photo-switching behavior). So, we can alter the conformation of the molecule using light, which will change the magnetic response of the
molecule, and this change
in the magnetic moment can
be recorded as a signal to
store data. To confirm this, we
have taken UV-Vis data for the
complex with and without laser
light irradiation, and the result
is astonishing; the conformation
of the molecule has changed
in the liquid state, confirming
its photo-switching behavior.
Also, the thermogravimetric
(weight loss or decomposition
of the sample with respect
to temperature) analysis has
found that the complex is stable at high temperatures (up to 485 K), which makes it a good candidate for storing data even at higher temperatures. Till now, we have been able to study such properties in the liquid state only.
Mr. Bijoy Dey || 475
So, now we are modifying the system such that we can observe such an effect in the solid state also. The optimization is still going on to obtain the best molecule that will induce
a huge magnetic moment on exposure to light. Then, we can deposit these molecules on a metal surface and use them for data storage applications.
The resulting increase in data storage capacity can be understood by comparison. At the tip of a needle, you will find more than one million molecules. Now, if each molecule behaves as a digit, then we will get 116 gigabytes of data. This space is enough to accommodate more than 25K songs, 200 movie films,
and millions of books. The amount of space we can get to ourselves is extraordinary if we achieve this goal, resulting in industrial and social revolution. So, it is a science mission with scientific and social relevance.
When we want to read or write the data, we can use a particular laser light that will magnetize certain molecules and the data will be stored. Therefore, the presence of laser light will then be counted as “1,” and its absence will be counted as “0” (Scheme 1).
Scheme 1. Schematic representation of the working principle of the molecule as a magnetic data storage material. 1. Before irradiation. 2. Molecule is demagnetized. 3. Demagnetized state registers
a binary signal corresponding to “0.” 4. Laser irradiation is used. 5. Conformation of the molecule changes. 6. After irradiation, the molecule is in a different conformation. 7. Molecule is magnetized or the magnetic response of the molecule is changed. 8. Different magnetic moment of the molecule registers another binary signal corresponding to “1.”