Larmor-en prezesioa kristaletan gertatzen diren aldaketen detektagailu

The study of the interplay between magnetic transitions and the crystal structure is crucial for the investigation of multiferroic materials. In fact, the structural changes across the magnetic transitions are usually the clue to ascribe the origin of the concomitant appearance of electric polarization. Nevertheless, in some materials, those structural variations are so small that their detection is very dicult. That is the case of MnWO4. Hence, in order to reach appropiate conclusions we need to use experimental techniques which are very sensitive to crystal structure variations. In this piece of work we present an experimental technique that takes prot of the precession of the neutrons in magnetic elds in order to see those small changes in the crystallographic structures, that is, the Larmor diraction by means of neutrons. Even if the obtained results are rather preliminary, the undoubtedly show the strength and power of this technique and the modications of the structure across the magnetic transitions.