Photoinduced melting of antiferromagnetic order in La(0.5)Sr(1.5)MnO4 measured using ultrafast resonant soft x-ray diffraction

H Ehrke; R I Tobey; S Wall; S A Cavill; M Först; V Khanna; Th Garl; N Stojanovic; D Prabhakaran; A T Boothroyd; M Gensch; A Mirone; P Reutler; A Revcolevschi; S S Dhesi; A Cavalleri

doi:10.1103/PhysRevLett.106.217401

Photoinduced melting of antiferromagnetic order in La(0.5)Sr(1.5)MnO4 measured using ultrafast resonant soft x-ray diffraction

Phys Rev Lett. 2011 May 27;106(21):217401. doi: 10.1103/PhysRevLett.106.217401. Epub 2011 May 25.

Authors

H Ehrke¹, R I Tobey, S Wall, S A Cavill, M Först, V Khanna, Th Garl, N Stojanovic, D Prabhakaran, A T Boothroyd, M Gensch, A Mirone, P Reutler, A Revcolevschi, S S Dhesi, A Cavalleri

Affiliation

¹ Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, United Kingdom.

PMID: 21699341
DOI: 10.1103/PhysRevLett.106.217401

Abstract

We used ultrafast resonant soft x-ray diffraction to probe the picosecond dynamics of spin and orbital order in La(0.5)Sr(1.5)MnO(4) after photoexcitation with a femtosecond pulse of 1.5 eV radiation. Complete melting of antiferromagnetic spin order is evidenced by the disappearance of a (1/4,1/4,1/2) diffraction peak. On the other hand, the (1/4,1/4,0) diffraction peak, reflecting orbital order, is only partially reduced. We interpret the results as evidence of destabilization in the short-range exchange pattern with no significant relaxation of the long-range Jahn-Teller distortions. Cluster calculations are used to analyze different possible magnetically ordered states in the long-lived metastable phase. Nonthermal coupling between light and magnetism emerges as a primary aspect of photoinduced phase transitions in manganites.