Science fiction is becoming science

These schematics of magnetic domain walls in perpendicularly magnetized thin films show (a) left-handed and (b) right-handed Neel-type walls; and (c) left-handed and (d) right-handed Bloch-type walls. The directions of the arrows correspond to the magnetization direction. Credit: Berkeley Lab

In the last few months I stumbled upon more and more news about quantum mechanics being studied for application in everyday world. It looks like it is getting out of theory and moving into practice.

Spintronics is a branch of physics studying the spin of electrons. In a broad sense electrons behaves like they are spinning (which they are not...) and they can spin in two directions that have been denoted by up and down. The spin is a quantum property and as such it comes in quantum steps. It is not like a top that can have a potentially infinite variation of spin velocity. In the case of electrons the spin is either +1/2 or -1/2 (as it is for all fermions -protons, neutrons-, whilst bosons -photons, mesons- have an integer spin value).

In a clump of matter electrons have spins in random direction (up and down), in magnetic material the majority of electrons have spin pointing in a specific direction (either up or down). Actually, it is this uniformity in spin direction that creates the magnetic property that we experience at the macro scale.

It gets more complicated. As electrons move around we experience their movement as a charge movement (they have a negative charge), in other word a current. This is exploited in all electronic devices where the flow of a current can be measured, altered and so on. This is what makes transistors useful.   Since electrons have spin too, they also have magnetic properties, i.e. generate a magnetic field. As they move around the atom nucleus in an orbit (again they don't move in a orbit like the Moon and the Earth, it is just a convenient way of understanding the macro properties we detect) their spin creates a magnetic field that can be measured.

Now researchers at the Berkeley Lab have discovered that it is possibile to alter this field, in a similar way as we alter a current. This opens the way to create sort of transistors based on spin, rather than on charge, and this would result in faster and much less energy hungrier processing devices.  By looking at their result you get many more "technical" detail but I guess that for most of us what I wrote is sufficiently complex.

What is amazing is to see that as scientists and researchers dig deeper into the understanding of Nature, more and more opportunities open up. What used to be science fiction just few years ago is now science and in a little while might become technology and engineering, finding a way into our homes and everyday life.

Author - Roberto Saracco

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