Structural and magnetic dynamics in the magnetic shape-memory alloy Ni2MnGa

Summary, in English

Magnetic shape-memory Heusler alloys are multiferroics stabilized by the correlations between electronic, magnetic, and structural order. To study these correlations we use time-resolved x-ray diffraction and magneto-optical Kerr effect experiments to measure the laser induced dynamics in a Heusler alloy Ni2MnGa film and reveal a set of time scales intrinsic to the system. We observe a coherent phonon which we identify as the amplitudon of the modulated structure and an ultrafast phase transition leading to a quenching of the incommensurate modulation within 300 fs with a recovery time of a few ps. The thermally driven martensitic transition to the high temperature cubic phase proceeds via nucleation within a few ps and domain growth limited by the speed of sound. The demagnetization time is 320 fs, which is comparable to the quenching of the structural modulation.

• Författare: S. O. Mariager; C. Dornes; J. A. Johnson; A. Ferrer; S. Gruebel; T. Huber; A. Caviezel; S. L. Johnson; T. Eichhorn; G. Jakob; H. J. Elmers; P. Beaud; Christoph Quitmann; G. Ingold
• Avdelning/ar: MAX IV-laboratoriet
• Publiceringsår: 2014
• Språk: Engelska
• Publikation/Tidskrift/Serie: Physical Review B (Condensed Matter and Materials Physics)
• Volym: 90
• Issue: 16
• Länkar: http://dx.doi.org/10.1103/PhysRevB.90.161103
• Dokumenttyp: Artikel i tidskrift
• Förlag: American Physical Society
• Ämne: Natural Sciences; Physical Sciences
• Aktiv: Published
• ISBN/ISSN/Övrigt: ISSN: 1098-0121