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MA: Fachverband Magnetismus

MA 25: Micro- and Nanostructured Magnetic Materials II

MA 25.7: Vortrag

Mittwoch, 25. März 2009, 16:15–16:30, HSZ 403

Critical behaviour of nanocrystalline gadolinium — •Adrian Ferdinand¹, Frank Döbrich¹, Anne Catherine Probst¹, Andreas Michels¹, Sharika Nandan Kaul², and Rainer Birringer¹ — ¹Technische Physik, Universität des Saarlandes, Saarbrücken, Germany — ²School of Physics, University of Hyderabad, Hyderabad, India

For single crystalline gadolinium (Gd), Srinath, Kaul, and Kronmüller [1] have demonstrated that Gd belongs to the uniaxial dipolar universality class with a Curie temperature T_c = 292.77 K. For polycrystalline Gd, the critical behaviour seems to be strongly affected by the microstructure when the crystallite size D is reduced to the nanometer regime. The most striking feature in this context is the continuous reduction of T_c with decreasing D which yields T_c-shifts of 10 K and more for grain sizes below 30 nm [2]. Here, we report on the critical behaviour of inert-gas condensed nanocrystalline Gd (with 8 nm < D < 21 nm) which has been studied by means of ac-susceptibility and small-angle neutron scattering.

[1] S. Srinath, S.N. Kaul, H. Kronmüller, Phys. Rev. B 59, 1145 (1999) [2] D. Michels, C.E. Krill III, R. Birringer, J. Magn. Magn. Mater. 250, 203 (2002)