An international team of researchers led by Lancaster University has discovered a highly efficient mechanism for shaking magnets using very short light pulses, shorter than a trillionth of a second.
Their research is published in the prestigious journal Physics Review Letters.
The discovery of new fundamental properties and phenomena in magnetic materials is essential for the development of faster and energy-efficient devices.
Using a very short electromagnetic pulse to shake the magnetization, researchers investigated its effect on the magnetization steering angle in two similar magnetic materials with different electronic orbitals. After shaking the magnet and subsequently analysing its magnetic state, they found that interaction between orbital motion and spinning enables a 10-fold larger spin deflection by the light pulse than the one without such interactions.
Lead author Dr Rostislav Mikhaylovskiy said: "We believe that this exciting discovery will stimulate further studies of the mechanisms governing the efficient and rapid control of magnetization for future quantum technologies."
Magnetic materials remain a significant part of our everyday lives, from refrigerator magnets memorabilia to compasses and magnetometers in our cell phones and personal computers. Large data centers rely on magnetic materials as data storage media, in which bits of information (i.e., "0" or "1") are encoded by the magnetization direction (i.e., "up" or "down").
The term "magnet" describes materials that can attract or repel other magnetic objects without touching them directly. In the simplest terms, the emergence of magnetism can be described by a model in which electrons orbit the atomic nucleus, analogous to planets orbiting the Sun. As the planets gyrate their rotational axes, the electrons exhibit a similar spinning. Due to the spinning, an electron behaves as an elementary magnet, called a "spin". The symmetry of electron orbital motion determines the direction of their spins, which can be thought of as a small "needle of a compass" pointing to "North" or "South" depending on the spin's polarity.
In materials, orbiting electrons of one atom interact with one another and with the electrons of neighboring atoms. These interactions determine the magnetization direction and the degree to which it is sensitive to the external stimulus. To steer the magnetization away from its steady-state direction, one may modify the electron orbital or the spin state directly. With strong enough steering, the magnetization direction can be reversed.
