Because it is difficult for transport electron spins to adhere to the magnetic texture of a magnetic domain, its walls are known to be a source of electrical resistance. This phenomenon has the potential to be used in spintronic devices, where the electrical resistance can change depending on whether a domain wall is present or not.
Half metals like La2/3Sr1/3MnO3 (LSMO), which have full spin polarization and can be used in spintronic devices, are a particularly intriguing group of materials. The resistance of a single half-metal domain wall was still unknown. Now, a group of researchers from Germany, France, and Spain have created a single domain wall on a LSMO nanowire and measured resistance changes that were 20 times larger than those of a typical ferromagnet like cobalt.
Spintronic applications may be possible thanks to the magnetic domain texture of magnetic domain walls. The presence or absence of domain walls affects ferromagnets’ electrical resistance. In spintronic memory devices, this binary effect, also known as domain wall magnetoresistance, could be used to encode information.
However, their use is hampered by the small changes in resistance that are observed in normal ferromagnets. Specifically noteworthy are manganite perovskites like LSMO. Due to the fact that these substances only exhibit one type of spin—full spin polarization—they may result in domain wall magnetoresistance effects that are significant enough to be utilized in a new generation of spintronic sensors and injectors.
Despite this promising outlook, the domain wall magnetoresistance values reported for this system are significantly off. Devices based on nanowires have been constructed by researchers from Germany, France, and Spain to enable the formation of individual magnetic domain walls. Magneto transport estimations in these gadgets show that the presence of a space wall prompts an increment of the electrical opposition of up to 12%. In outright terms, the observed opposition change is multiple times bigger than that detailed for cobalt.
Film growth and nanofabrication, transport measurements, contact microscopy (MFM) imaging, theoretical simulations, and the application of cutting-edge characterization methods like X-ray photoemission electron microscopy all play a role in this ongoing collaboration. The blend of a wide range of methods gives an exhaustive multi-layer perspective on a mind-boggling issue, which has permitted new experiences in an exceptionally discussed open inquiry.
The study has been published in the Advanced Materials journal.
More information: Gloria Orfila et al, Large Magnetoresistance of Isolated Domain Walls in LSMO Nanowires, Advanced Materials (2023). DOI: 10.1002/adma.202211176
