Energy of Flipping A Spin

We found that the physics of using a spin’s orientation to store data fundamentally differs from that of using a particle’s position as a (classical) bit of information: the former is quantum dynamic and independent of temperature (if the temperature is below the Curie point), whereas the latter is thermodynamic and thereby dependent on temperature. The formula to calculate the minimum energy of flipping a spin should be the Bohr magneton times the magnetic field. Obviously, the key to calculating such a minimum energy is to find a minimum magnetic field that should not be zero; otherwise, spin-flipping will not take place. Our conclusion is that the energy limit of storing data in a modern way (using a spin’s orientation) is 1.64E-36 J, 15 orders of magnitude lower than that of storing data in a classical way (using a particle’s position), which implies that spin electronics in data storage is fundamentally superior to classical charge-based methods in terms of energy efficiency and computational reversibility. We also verified this new limit based on a spinspin interaction experiment.