A complex process can modify non-magnetic oxide materials in such a way to make them magnetic. The basis for this new phenomenon is controlled layer-by-layer growth of each material. An international research team with researchers from Martin Luther University Halle-Wittenberg (MLU) reported on their unexpected findings in the journal "Nature Communications".
In solid-state physics, oxide layers only a few nanometres thick are known to form a so-called two-dimensional electron gas. These thin layers, separated from one another, are transparent and electrically insulating materials. However, when one thin layer grows on top of the other, a conductive area forms under certain conditions at the interface, which has a metallic shine. "Normally this system remains non-magnetic," says Professor Ingrid Mertig from the Institute of Physics at MLU. The research team has succeeded in controlling conditions during layer growth so that vacancies are created in the atomic layers near the interface. These are later filled in by other atoms from adjoining atomic layers.
The theoretical calculations and explanations for this newly discovered phenomenon were made by Ingrid Mertig’s team of physicists. The method was then experimentally tested by several research groups throughout Europe - including a group led by Professor Kathrin Dörr from MLU. They were able to prove the magnetism in the materials. "This combination of computer simulations and experiments enabled us to decipher the complex mechanism responsible for the development of magnetism," explains Mertig.
The study builds upon the work of the former Collaborative Research Centre 762 "Functionality of Oxide Interfaces" at MLU, which was funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) from 2008 to 2019.
Reference:
The emergence of magnetic ordering at complex oxide interfaces tuned by defects
D.-S. Park, A. D. Rata, I. V. Maznichenko, S. Ostanin, Y. L. Gan, S. Agrestini, G. J. Rees, M. Walker, J. Li, J. Herrero-Martin, G. Singh, Z. Luo, A. Bhatnagar, Y. Z. Chen, V. Tileli, P. Muralt, A. Kalaboukhov, I. Mertig, K. Dörr, A. Ernst & N. Pryds
Published: 20 July 2020
doi: 10.1038/s41467-020-17377-0
Contact information:
Prof. Dr. Ingrid Mertig
Institut für Physik
ingrid.mertig@physik.uni-halle.de
+49 345 55-25430
Waste polyamide-derived CQDs show continuous photoluminescence tuning from 308 to 552 nm through sequential defect-state engineering, with optical transition energies decreasing from 4.32 to 2.50 eV. @Christian Ebere Enyoh from Saitama University Carbon quantum dots (CQDs) are fluorescent carbon nanomaterials with potential applications in sensing, optoelectronics, displays, anti-counterfeiting, and environmental technologies. Their optical properties can be adjusted by modifying the carbon...
The researchers used circularly polarized light at normal incidence and found that helicity-dependent photocurrents appeared perpendicular to the crystal’s polarization but vanished when measured parallel to it, supporting a bulk origin of CPGE. @Institute of Science Tokyo The circular photogalvanic effect (CPGE), a phenomenon that generates helicity-dependent photocurrents in noncentrosymmetric materials, can originate purely from a crystal's internal structure without contribution from the...
Summary of gold nanoparticle growth programming in liposome based on localization of biomineralization peptide The position of biomineralization peptides within liposomes can influence how gold nanoparticles grow, reports a research team from Institute of Science Tokyo. Peptides localized at the membrane interface promote branched structures, while those confined to the liposome interior favor spherical nanoparticles. The findings offer a new strategy for controlling nanoscale reaction...
