Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 3: Magnetic Materials I
MA 3.9: Vortrag
Montag, 26. März 2007, 12:15–12:30, H22
Unexpectedly Strong Magnetic Coupling in Rare Earth Borides — •Takao Mori1,2 and Yuri Grin2 — 1National Institute for Materials Science, Nanoscale Materials Center, Namiki 1-1, Tsukuba, 305-0044, Japan — 2Max Planck Institute for Chemical Physics of Solids, Noethnitzer Str. 40, 01187 Dresden, Germany
The magnetism of rare earth borides like REB4, REB6, and REB12 has attracted a lot of interest over the years. These compounds are all good metals in the case of trivalent rare earth elements and their magnetic coupling has basically been described by the Ruderman-Kittel-Kasuya-Yoshida (RKKY) mechanism. As an emerging new phenomenon, it has been found that borides which contain the B12 icosahedra as a structural building block can exhibit unexpectedly strong magnetic interactions despite being relatively magnetically dilute insulators (e.g. TN = 17 K for TbB50 and Tf = 29 K for HoB17CN) [1-3]. We report on a new phase discovered in a series of homologous rare earth boron carbonitride compounds which have a particular triangular configuration of the rare earth atoms. The dynamical properties investigation of HoB22C2N has previously indicated that it is a two-dimensional spin glass. Magnetic and thermoelectric properties of this series of compounds are presented.
[1] T. Mori and T. Tanaka, J. Phys. Soc. Jpn. 68 2033 (1999). [2] T. Mori and H. Mamiya, Phys. Rev. B 68, 214422 (2003). [3] T. Mori, J. Appl. Phys. 95, 7204 (2004).