By Josh Perry, Editor
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Researchers at the University of Arkansas (Fayetteville, Ark.) are studying bismuth ferrite (BFO), which is a material that shows potential for storing information more efficiently than currently possible, as well as being used in sensors, transducers, and other electronics.

Researchers hope that BFO could be a new material for more efficient information storage.
(Wikimedia Commons)

According to a report from the school, BFO responds to both electrical and magnetic fields and has the potential to store information. Its magnetoelectric response is small, so researchers are working on building conditions that would improve its response to use electricity rather than magnetism to store information.

The goal is to create a system that reduces the amount of energy that the process requires, most of which is currently wasted as excess heat and reduces overall performance.

“The researchers also documented the phenomenon responsible for the enhanced response, which they called an ‘electroacoustic magnon,’” the article continued. “The name reflects the fact that the discovery is a mix of three known ‘quasiparticles,’ which are similar to oscillations in a solid: acoustic phonons, optical phonons and magnons.”

The research was recently published in Physical Review Letters. The abstract stated:

“An atomistic effective Hamiltonian scheme is employed within molecular dynamics simulations to investigate how the electrical polarization and magnetization of the multiferroic BiFeO3 respond to time-dependent ac magnetic fields of various frequencies, as well as to reveal the frequency dependency of the dynamical (quadratic) magnetoelectric coefficient.

“We found the occurrence of vibrations having phonon frequencies in both the time dependency of the electrical polarization and magnetization (for any applied ac frequency), therefore making such vibrations of electromagnonic nature, when the homogeneous strain of the system is frozen (case 1).

“Moreover, the quadratic magnetoelectric coupling constant is monotonic and almost dispersionless in the sub-THz range in this case 1. In contrast, when the homogeneous strain can fully relax (case 2), two additional low-frequency and strain-mediated oscillations emerge in the time-dependent behavior of the polarization and magnetization, which result in resonances in the quadratic magnetoelectric coefficient.

“Such additional oscillations consist of a mixing between acoustic phonons, optical phonons, and magnons, and reflect the existence of a new quasiparticle that can be coined an ‘electroacoustic magnon.’

“This latter finding can prompt experimentalists to shape their samples to take advantage of, and tune, the magnetostrictive-induced mechanical resonance frequency, in order to achieve large dynamical magnetoelectric couplings.”