BCMaterials Invited Talk: Sergey Kustov " “Microeddy Bordoni-type relaxation controls spin glass transitions?”

Next Thursday 18th BCMaterials and ZTF-FCT (UPV-EHU) present a Sergey Kustov Talk: “ Microeddy Bordoni-type relaxation controls spin glass transitions!?"
Seminario del Departamento de Electricidad y Electrónica 12:00 p.m.
Acoustic techniques have not so far been used to study magnetic domain wall freezing effect typical for re-entrant spin glass transitions. Application of this method, which includes simultaneous measurements of linear microeddy and non-linear hysteretic magnetomechanical damping, to various materials having relatively low Curie temperatures (pure element – Dy, several types of ferromagnetic bulk metallic glasses, BMG), reveals the following regularities:
- a strong decrease of the long-range mobility of domain walls (or domain wall “freezing” effect) is controlled by a discovered linear microeddy current anelastic relaxation phenomenon;
- the microeddy relaxation is accompanied by a number of effects typical for the re-entrant spin glass transition as anomalies in magnetization, coercive force, magnetostriction, broken ergodicity;
- the microeddy current relaxation, which controls seemingly all (low field) magnetic properties is observed in completely different (in terms of crystallography and magnetism) materials, like pure Dy and BMGs;
- once the Curie temperature falls below the relaxation temperature, the re-entrant spin glass transition transforms into the spin glass one;
Based on the similarity of microeddy relaxation features in different ferromagnetic systems we propose that the relaxation is related to intrinsic properties of domain walls. We draw an analogy between the observed magnetic relaxation and the Bordoni anelastic relaxation due to the kink pair formation on a dislocation line.
One can assume that similar intrinsic properties of topological defects (domain walls) might control “glassy” transitions in other physical systems, like ferroelectrics and martensites

Related news
Meeting of the new BCMaterials Board of Trustees
On April 1st, BCMaterials facilities held the center’s new Board of Trustees meeting. The Board reviewed BCMaterials overall situation and examined the results and activities reported in the 2024…Track the Twin: Digital Twins to Improve Quantum Dots
The Marie Curie doctoral network "Track the Twin," in which BCMaterials is participating, is already underway. This project aims to enhance the long-term performance of quantum dots through the…Maibelin Rosales, in the Periodic Table of Chilean Female Scientists
We would like to congratulate our Marie Curie postdoctoral researcher, Maibelin Rosales, for being selected as one of the 118 researchers recognized in the Periodic Table of Chilean Female Scientists…Esraa Sewlam and Lía Campos, New Doctors of BCMaterials
We would like to extend our sincere congratulations to pre-doctoral researchers Esraa Sewlam and Lía Campos Arias for obtaining their PhDs in Materials Science and Technology from the UPV/EHU.…