Magnetic heterostructure generates higher frequencies for information processing

Novel magnetic recollections are energy-efficient and sturdy. They're primarily based on ferromagnets with working frequencies within the gigahertz vary. The working frequency may very well be additional elevated with antiferromagnets, which, nonetheless, can't be effectively excited.

Researchers from Kaiserslautern and Mainz have now proven that magnetic heterostructures—primarily based on a skinny antiferromagnet/ferromagnet bilayer—can mix the benefits of each materials lessons: A excessive working frequency with environment friendly excitation. The work has been revealed within the journal Bodily Assessment Letters and has been highlighted as an Editors’ suggestion.

Magnetic supplies play a central function in info processing and transmission in digital gadgets. “We distinguish between completely different lessons of magnets,” says Professor Dr. Mathias Weiler, who heads the Utilized Spin Phenomena group of the Division of Physics on the College Kaiserslautern-Landau.

“The ferromagnets have a web magnetization and are used as everlasting magnets, which produce a stray subject. They're straightforward to excite. Their dynamics are within the gigahertz vary.”

A second class of magnetic supplies behaves fairly in another way: antiferromagnets. “From the surface, you possibly can’t inform that they've magnetization. They don’t present any web magnetic second that you would be able to work together with. This makes them tough to excite,” explains Ph.D. scholar Hassan Al-Hamdo, first writer of the present research.

As soon as they're excited, nonetheless, they exhibit a lot quicker dynamics within the terahertz vary. This truth makes them fascinating for numerous fields of software, comparable to communication applied sciences and magnetic recollections, because the processing velocity may very well be accelerated considerably. “Nevertheless, since antiferromagnets can't be excited effectively, their functions are restricted,” Weiler continues.

Along with analysis colleagues from Mainz, the researchers in Kaiserslautern have now proven how the quicker dynamics of antiferromagnets can however be used. For his or her experiments, they relied on a hybrid materials. “It consists of two skinny layers, one ferromagnetic and one antiferromagnetic,” explains Weiler. The ferromagnetic layer is a standard nickel-iron compound that can also be present in transformers, for instance. The antiferromagnetic layer is a manganese-gold compound.

The particular characteristic of the heterostructure is discovered within the association of the spins instantly on the antiferromagnetic-ferromagnetic interface. Al-Hamdo states, “The spin describes the intrinsic angular momentum of a quantum particle and is the idea of all magnetic phenomena. On the interface, we discover a well-defined order of the spins.

“This results in an unusually robust coupling of the antiferromagnetic and ferromagnetic spins. The coupling is so pronounced that the spins of the antiferromagnet align themselves primarily based on the magnetization within the ferromagnet. This property is exclusive.”

The heterostructure was developed by colleagues at Johannes Gutenberg College Mainz. Colleagues in Mainz additionally developed the theoretical mannequin to clarify the experimental outcomes from Kaiserslautern.

“By utilizing the distinctive properties of our heterostructure, we succeeded in transferring a magnetic excitation from the ferromagnet to the antiferromagnet. In doing so, we've obtained the next frequency than is the case with the pure ferromagnet. The frequency is between that of the antiferromagnet and the ferromagnet,” Weiler says.

These outcomes are fascinating for future functions. “For rising cell functions, increased frequencies will probably be wanted,” Weiler cites for example. “With this coupling, we're stepping into these areas.” Fields of software is also reminiscence applied sciences comparable to Magnetic Random-Entry Reminiscence or microwave era by means of spin-torque oscillators, the place increased frequencies would enhance efficiency.