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MA: Fachverband Magnetismus
MA 9: Magnetic Materials I
MA 9.3: Talk
Monday, March 14, 2011, 15:15–15:30, HSZ 401
Structural, magnetic and electronic properties of a new silicide MnPtSi — •Monika Gamza1,2, Sarah Ackerbauer1, Andreas Leithe-Jasper1, Walter Schnelle1, Helge Rosner1, and Yuri Grin1 — 1MPI CPfS Dresden — 2Institute of Materials Science, University of Silesia, Katowice, Poland
Recent results concerning giant exchange-derived magnetoelastic coupling in a metamagnet MnCoSi (TiNiSi-type structure) [1] as well as intriguing magnetic properties of the isostructural compounds MnTX (T = transition metal element; X = Si, Ge) [2] prompted us to search for consecutive members of this family.
Here, we report on the crystal structure, electronic structure and magnetic properties of the new compound MnPtSi. The Mn K XAS data indicate a divalent state of Mn ions. The effective moment derived from high-temperature magnetic susceptibility of 4.1µB indicates an intermediate spin state of Mn ions. These findings have been confirmed by first principles electronic structure calculations. Thermodynamic measurements revealed two successive magnetic phase transitions at TC≈ 350 K and TN≈ 326 K. The FM to AFM transition is accompanied by a large magneto-volume effect (ΔV/V reaches ∼1.4%) and a change in Mn-Mn distances of up to 1%. The origin of the strongly anisotropic thermal expansion is analyzed.
[1] Barcza A. et al., Phys. Rev. Lett. (2010) 104 247202
[2] Eriksson T. et al., Phys. Rev. B (2005) 71 174420 and references there in