Despite significant advances in the capacity of data storage in electronic media, the need for denser storage capacity continues unabated.
Technological developments in this field still trail behind the exponential growth of information storage needs. It is becoming harder to increase memory capacities while simultaneously making them smaller and faster. In spite of this, the ongoing attempts to develop alternative storage technologies, especially in smaller devices, have yielded yet another breakthrough in terms of storage density.
Researchers from the North Carolina State University (NCSU) have developed a novel material that is capable of storing 50 times more data than comparable chips available today. The new material synthesised by the researchers shows promising magnetic properties that would enable a chip the size of a fingernail to handle as much as 1 TB (Terabyte, equal to 1024 Gigabytes).
The breakthrough was achieved by adding nickel (Ni) to magnesium oxide (MgO) and modifying the electrical properties of the resulting compound through selective doping. The groundbreaking research was spearheaded by Jagdish Narayan, professor of materials science and engineering at NSCU, and the work is described in a recent issue of the journal JOM. Narayan and team synthesised the Ni-MgO system and, while investigating its magnetic properties, realised that at certain conditions it acts as a perfect paramagnet. Specifically, the engineers were able to induce clustering of Ni ion precipitates on substitutional Mg sites, which can be varied by modifying the annealing time and temperature as per requirements.
Paramagnetism is a form of magnetism occurring only in the presence of an externally applied magnetic field. Unlike ferromagnets, paramagnets do not retain any magnetisation in the absence of an external field, because thermal motion causes the spins to become randomly oriented without it. Thus the total magnetisation will drop to zero when the applied field is removed. The attraction experienced by ferromagnets is non-linear and much stronger, so that it is easily observed, for instance, in magnets on one’s refrigerator.
The team also established clear structure-property correlations to explain the magnetic properties of specimens that ranged from perfectly paramagnetic to fully ferromagnetic. Based on these studies, the researchers were able to clearly ascertain that the clusters of nickel atoms about 10 square nanometres in size could act as memory elements, which would result in over 90% reduction in memory size compared to contemporary devices.
In addition to its applications in data storage, this material also holds significant potential for the field of spintronics. The researchers were able to successfully control the electron spin by manipulating the material, consequently paving the way for harnessing the energy in the electrons’ spin. Spintronics can be exploited for developing more efficient semiconductors as well as efficient memories that dissipate considerably less heat.
Besides holding considerable potential for applications in information storage, the novel Ni-MgO material could also be put to use for the development of ceramic engines with enhanced fuel economies, and the ability to withstand twice the temperatures of normal engines. Moreover, the excellent thermal conductivity of the material is also quite promising for harnessing alternative energy sources such as solar energy.
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