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MA: Magnetismus
MA 15: Spin-Dependent Transport Phenomena II
MA 15.3: Talk
Tuesday, March 28, 2006, 10:45–11:00, HSZ 103
Point contact Andreev-reflection spectroscopy of ferromagnetic thin films — •Jan M. Scholtyssek, Lars Bocklage, Rainer Anton, Ulrich Merkt, and Guido Meier — Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstr. 11, 20355 Hamburg
The spin polarisation at the Fermi energy is one of the key properties of ferromagnetic materials in the field of spintronics. We measure the spin polarisation of the conduction electrons using point contact Andreev-reflection spectroscopy (PCAR) [1]. To verify the accuracy of the method measurements on 100 nm thick Ni and Au films are performed. For the interface between the halfmetallic Heusler alloy Ni2MnIn and InAs a spin polarisation of 100% is predicted [2]. We fabricate Ni2MnIn films with thicknesses between 30 nm and 100 nm by coevaporation of Ni and a MnIn alloy from two independent sources [3]. Stoichiometric and morphological investigations of the Heusler films deposited on amorphous carbon films are performed in a transmission electron microscope. We present resistivity and PCAR measurements of samples grown on Si exhibiting an enhanced spin polarisation in comparison to the 3d-ferromagnets.
[1] R.J. Soulen, et. al. Science 282, 85(1998)
[2] K.A. Kilian and R.H. Victora. J. Appl. Phys. 87, 7064(2000)
[3] M. Kurfiß, et. al. JMMM 290, 591(2005)