Photoinduced femtosecond relaxation of antiferromagnetic orders in the iron pnictides revealed by ultrafast laser ellipsometryA. Patz, T. Li, S. Ran, S. Bud’ko, P. Canfield and J. WangEPJ Web of Conferences, 41 (2013) 03011DOI: https://doi.org/10.1051/epjconf/20134103011