Dresden 2014 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 20: Correlated Electrons: Spin Systems and Itinerant Magnets - Frustrated Magnets II
TT 20.11: Vortrag
Montag, 31. März 2014, 17:45–18:00, HSZ 304
Magnetic properties of intermetallic AT4X2 compounds — •Vivien Lorenz, Inga Kraft, Christoph Bergmann, Katharina Weber, Nandang Mufti, Christoph Geibel, and Helge Rosner — Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
Magnetic systems with reduced dimensionality or frustration attract strong interest because these features lead to an increase of quantum fluctuations and often result in unusual properties. The vicinity of magnetic and non magnetic states can further increase the fluctuations. Here, we present a detailed density-functional-based study of the electronic, magnetic and structural properties of the intermetallic AT4X2 compounds (A=Sc,Y,Lu,Zr,Hf; T=Fe,Ni,Re; X=Si,Ge,P,As) crystallizing in the ZrFe4Si2 structure type. Magnetic and structural transitions were previously reported for YFe4Ge2 and closely related compounds with trivalent A-site occupation. However, transition temperatures, nature of the transition as well as the relation between structural and magnetic transitions change significantly with the A element. Our calculational results evidence that: (i) all investigated T=Fe compounds have a magnetic ground state; (ii) all investigated T=Ni systems are non magnetic, but several of them are very close to magnetism; (iii) the magnetic properties of these compounds can be "tuned" by partial substitution on the T and X site. We also study the instability towards a structural distortion related to strong magneto-elastic coupling. Our findings will be compared to recent experimental results.