Delft University of Technology scientists have achieved the manipulation of spin waves on a chip utilizing superconductors, marking a significant stride towards energy-saving technology and quantum computing progression.
Superconductors have been employed by physicists to influence spin waves on chips, setting the foundation for advancements in energy-conserving technology and quantum computing.
Quantum physicists at Delft University of Technology have demonstrated the capability to manage spin waves on a chip through superconductors. This phenomenon in magnets could potentially provide a substitute for conventional electronics, beneficial for energy-efficient IT or components of a quantum computer. The discovery, documented in the journal Science, primarily offers physicists a deeper comprehension of the relationship between magnets and superconductors.
Energy-Efficient Alternative
Michael Borst, the experiment’s head, elaborates, “Spin waves are magnetic material waves used for information transmission.” Owing to the potential of spin waves as an energy-saving alternative to electronics, there has been ongoing research to find an optimal method to manage them for some time.
Although theories have proposed that metal electrodes can regulate spin waves, only recently have physicists observed such effects experimentally. Toeno van der Sar, an Associate Professor in Quantum Nanoscience, notes, “Our research has established that proper control over spin waves is attainable with a superconducting electrode.”
Superconducting Reflection
Here’s how it functions: a spin wave produces a magnetic field, which subsequently prompts a supercurrent in the superconductor. This supercurrent mirrors the spin wave: the superconductor reflects the magnetic field back. The reflective property of the superconductor slows the spin waves, rendering them more manageable. Borst adds, “The wavelength of spin waves dramatically shifts when they traverse under the superconducting electrode. By minutely adjusting the electrode’s temperature, we can precisely alter the degree of this shift.”
The experiment is depicted with two gold electrodes placed over a magnetic layer, and between them lies a superconducting electrode. Spin waves are initiated in the magnetic substance by the left gold electrode. Above these electrodes sits a diamond membrane, granting the scientists a clear view through the superconductor.
Van der Sar describes the process, “We initiated with a thin yttrium iron garnet (YIG) magnetic layer. A superconducting electrode was placed atop it, followed by another electrode to produce spin waves. Cooling to -268 degrees transitioned the electrode to a superconductive state. Observing the gradual slowing of the spin waves as the temperature dropped was fascinating. This provides us with a distinct mechanism to manipulate these waves and deepens our understanding of superconductors.”
Pioneering Sensor
To visualize the spin waves, the magnetic field was measured using a unique sensor. Van der Sar states, “Electrons in diamonds serve as our sensors for the spin waves’ magnetic fields. This method, pioneered by our lab, allows us to peer through the non-transparent superconductor to observe the underlying spin waves, akin to an MRI viewing through skin.”
The Future of Circuits
Borst mentions, “Spin wave technology is in its initial stages. To build energy-efficient computing systems using this tech, we must first construct small circuits for computational tasks. Our finding presents an opportunity: superconducting electrodes facilitate the creation of numerous energy-saving spin wave circuits.”
Van der Sar concludes, “We’re now in a position to engineer devices harnessing spin waves and superconductors that emit minimal heat and sound waves. This can lead to the spintronics equivalent of certain electronic components found in mobile phones or even act as links between qubits in quantum computers.”
Source: “Observation and control of hybrid spin-wave–Meissner-current transport modes” by M. Borst, et al., 26 October 2023, Science. DOI: 10.1126/science.adj7576.
