Researchers at the University of Konstanz have developed a method to synthesize europium oxide (II) nanoparticles, a ferromagnetic semiconductor associated with data storage and transmission
Ferromagnetic semiconductors are promising functional materials for spintronics (spintronics). Spintronics is essential for the storage and transmission of information. The researchers also demonstrated that the magnetic properties of nanoparticles are given by their structure. The results of the joint research project have been published in the scientific journal Advanced Materials on 20 November 2017.
The properties of anisotropic and magnetic nanoparticles are at the heart of the research project. Anisotropy means that shape and magnetism, optical or electronic properties are not the same for all spatial orientations of particles. This in turn makes it possible to study not only new and often improved properties of nanostructured materials, but also additional properties caused by anisotropy.
Manufacturing nanoparticles from ferromagnetic semiconductors such as Europium oxide (II) poses significant challenges, particularly in anisotropic geometry. “Our goal is to deepen our understanding so that we can tailor and capture the properties of nanosystem-based systems on demand,” said Trepka, the lead author. Using their special method, the researchers succeeded in producing high-quality anisotropic EuO nanoparticles that could be used to observe structural effects.
The method is based on a two-stage process. In the first step, a mixture of organic and inorganic components is produced, which is already anisotropic. In the next step, the mixture is treated with europium vapor. As a result, it’s chemically converted to EuO. In this case, the nanoparticles are tubular in shape. “This approach is interesting because it’s not limited to the tubular form. It can also produce rods, “explained Bastian Trepka.
In addition, the researchers were able to show that the magnetism of the semiconductor europium (II) oxide was actually related to the shape of its nanostructure, or anisotropy. When further processing is performed while attempting to produce counterevidence, the tubular shape disappears, leading to different properties. “Experimental physicists have made measurements that confirm the results that theoretical physicists have simulated. This allows us to come up with ideas about how the structure produces this particular magnetic behavior, “explained Bastian Trepka.
“What’s really special about our process is the separation of structural control and chemical transformation. We can influence the shape through process control to get different shapes from the same material. “In this way we can always get the material to take on the shape we want,” Says Trepka. In the case of europium (II) oxide, this is a nanoshift towards maintaining its crystalline orientation: it is tubular before and after treatment.
“Intelligent materials with a variety of properties,” says Bastian Trepka of Europium (II) oxide. Most importantly, it has a simple crystal structure. “We can explain the changes in properties and be attractive to pre-determined crystal structures.” This is ideal for basic research.
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