Regensburg 2010 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 27: Spin Structures and Magnetic Phase Transitions
MA 27.5: Vortrag
Donnerstag, 25. März 2010, 18:15–18:30, H10
Magnetic Spin Configuration in Fe50Pt50−xRhx alloys — •J. Fenske1, D. Lott1, G.J. Mankey2, W. Schmidt3, K. Schmalzl3, E. Tartakowskaya4, and A. Schreyer1 — 1GKSS Research Centre — 2The University of Alabama, MINT Center — 3Juelich Research Centre — 4Institute for Magnetism, National Ukrainian Accademy of Science
FePt-based alloys are typically the material of choice for magnetic information storage media. The high magnetic moment of Fe gives a large magnetization and the large atomic number of Pt results in a high magnetic anisotropy. This combination enables the written bits to be smaller than ever before. One way to control the magnetic properties in these materials is through the introduction of a third element into the crystal matrix e.g. Rh. When Rh is added to replace Pt in the equiatomic alloy, new magnetic phases emerge. Bulk samples of Fe50Pt50−xRhx studied by magnetization measurements refer to three different phase transitions with increasing temperature: (I) An antiferromagnetic (AF) - paramagnetic (PM) transition for 30< x <14.25, (II), an AF - ferromagnetic (FM) transition for 14.25< x <9.5 and, (III), a FM - PM transition 9.5< x <0 [1]. Here we present results on a series of 200nm Fe50Pt50−xRhx films with different Rh concentrations. These films were examined by neutron diffraction in dependence of temperature and magnetic field. By the use of polarized and unpolarized neutron diffraction we could develop a detailed model of the magnetic spin structure in these thin films. [1] S. Yuasa, H. Miyajima and Y. Otani, J. Phys. Soc. Jpn. 63 (8), 1994