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arXiv · 1106.6128

Femtosecond dynamics of the collinear-to-spiral antiferromagnetic phase transition in CuO

S. L. Johnson·R. A. de Souza·U. Staub·P. Beaud·E. Möhr-Vorobeva·G. Ingold·A. Caviezel·V. Scagnoli·W. F. Schlotter·J. J. Turner·O. Krupin·W. -S. Lee·Y. -D. Chuang·L. Patthey·R. G. Moore·D. Lu·M. Yi·P. S. Kirchmann·M. Trigo·P. Denes·D. Doering·Z. Hussain·Z. -X. Shen·D. Prabhakaran·A. T. Boothroyd
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Abstract

We report on the ultrafast dynamics of magnetic order in a single crystal of CuO at a temperature of 207 K in response to strong optical excitation using femtosecond resonant x-ray diffraction. In the experiment, a femtosecond laser pulse induces a sudden, nonequilibrium increase in magnetic disorder. After a short delay ranging from 400 fs to 2 ps, we observe changes in the relative intensity of the magnetic ordering diffraction peaks that indicate a shift from a collinear commensurate phase to a spiral incommensurate phase. These results indicate that the ultimate speed for this antiferromagnetic re-orientation transition in CuO is limited by the long-wavelength magnetic excitation connecting the two phases.

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S. L. Johnson, R. A. de Souza, U. Staub, P. Beaud, E. Möhr-Vorobeva, G. Ingold, A. Caviezel, V. Scagnoli, W. F. Schlotter, J. J. Turner, O. Krupin, W. -S. Lee, Y. -D. Chuang, L. Patthey, R. G. Moore, D. Lu, M. Yi, P. S. Kirchmann, M. Trigo, P. Denes, D. Doering, Z. Hussain, Z. -X. Shen, D. Prabhakaran, A. T. Boothroyd. 2011-06-30. Femtosecond dynamics of the collinear-to-spiral antiferromagnetic phase transition in CuO. https://doi.org/10.1103/physrevlett.108.037203

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