Berlin 2012 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 38: MagneticThin Films I
MA 38.11: Vortrag
Donnerstag, 29. März 2012, 12:15–12:30, H 0112
Structural and magnetic dynamics of a laser induced phase transition in FeRh — •Federico Pressacco1, Simon O. Mariager2, Eduardo Mancini1, Andrin Caviezel2, Ekaterina Vorobeva2, Paul Beaud2, Steven L. Johnson2, Chris Milne3, Eric Fullerton4, Robert Feidenhans’l5, Christoph Quitmann2, Gerhard Ingold2, and Christian H. Back1 — 1Universität Regensburg, 93053 Regensburg, Deutschland — 2SLS, Paul Scherrer Institute, 5232 Villigen, Switzerland — 3Ecole Polytechnique Federal Lausanne, 1015 Lausanne, Switzerland — 4University of California, San Diego, La Jolla, CA 92093-0401, USA — 5Niels Bohr Institute, University of Copenhagen, 2100 Kobenhavn, Denmark
The FeRh compound shows an extraordinary onset of a net magnetization with the increase of temperature starting from a antiferromagnetic room temperature ground state. The effects of the transition can be detected also in a change of the structural order accompanied with a isotropic volume expansion of about 1 percent. We used time-resolved x-ray diffraction and magnetic optical Kerr effect to study the laser induced antiferromagnetic to ferromagnetic phase transition in FeRh. The structural response is given by the nucleation of independent domains (t1=30 ps). This is significantly faster than the average magnetic response (t2=100 ps) which is given by the subsequent domain realignment. X-ray diffraction shows that two phases co-exists on a short time scale. We present a simple model that, assuming a simultaneous nucleation of structural and magnetic domains, accounts well both dynamics on a sub-nanosecond time scale.