In collaboration with researchers from MFF UK3 and colleagues from United Kingdom and Japan we have introduced a new principle of an antiferromagnetic-based spintronic device and its implementation. Currently used spintronic elements in hard disk read-and-write heads or memory chips are based on ferromagnets. Electron spins tends to arrange themselves in one direction in ferromagnets which therefore work as a strong magnet. There is however much larger family of materials in which the spins are arranged in one direction around particular group of atoms and in opposite direction around another group. These so-called antiferromagnets draw attention because they show magnetism inside but not outside them. Antiferromagnetic materials thus do not magnetically affect each other – this is valuable characteristics especially with regard to elements density in present-day integrated circuits. So far, there were however no evidence of principle on which could antiferromagnetic-based spintronic device work. We have introduced not only such principle but even an experimantal realization of the particle. We showed that the electric resistance changes significantly when spins rotate similarly to classical ferromagnetic spintronic elements. This quantum-relativistic effect is remarkable not only for its possible applications in spintronics but also for better understanding of elementary physical properties of solids. Spintronic devices were so far restricted to metallic ferromagnets – the antiferromagnets now represents much larger and varied group of materials with metallic or semiconductor characteristics that could be used for spintronic research and its applications in sensors and computer microdevices.