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

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. Kustov 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

See all news
  • Amaia Zarandona, New Doctor of BCMaterials

    News

    We would like to congratulate Amaia Zarandona Rodríguez for obtaining her PhDs in Materials Science and Technology from the UPV/EHU. On May 22, Amaia made a brilliant defense of her thesis titled “…
  • Pablo Docampo, New Ikerbasque Professor at BCMaterials

    News

    We are glad to welcome Pablo Docampo as new Ikerbasque Research Professor at BCMaterials. Prof. Docampo received his DPhil in 2012 from the University of Oxford focussing on the electronic…
  • Invited Talk with Aaron Mailman (May 20th)

    Events

    BCMaterials is proud to host Dr. Aaron Mailman, Academy of Finland Research Fellow at the University of Jyväskylä (Finland) in a new invited talk. The talk is titled: “Organic Radicals as Functional…
  • Qi Zhang Appointed Visiting Professor at NUAA (China)

    Awards

    Our Ikerbasque Research Professor, Qi Zhang, was appointed visiting professor at Nanjing University of Aeronautics and Astronautics (NUAA) this April. Zhang, who has an extensive research career in…