Berlin 2005 – wissenschaftliches Programm
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MA: Magnetismus
MA 20: Poster:Schichten(1-29),Spintrsp(30-45),Ex-Bias(46-63),Spindyn(64-75),Mikromat.(76-80),Cluster(81-94),Abbv.(95-99),Obflm(100-02),SpElek.(103-09),E-Theo(110-14),Mikromag.(115-16),Spin+PÜ(117-26),Mag.Mat.(127-51),Meth.(152-55),Mol.Mag(156-59),Kondo(160-65
MA 20.145: Poster
Montag, 7. März 2005, 14:00–18:00, Poster TU C
Magnetic and electrical properties of intermetallic ternary rare earth compounds — •H. Hartmann1, O. Heyer1, S. Jodlauk1, K. Kordonis1, T. Lorenz1, A. Freimuth1, T. Fickenscher2, and R. Pöttgen2 — 1II. Physikalisches Institut, Universität zu Köln, 50937 Köln — 2Anorganisch-Chemisches Institut, Universität Münster, D-48149 Münster
We present measurements of the magnetization M, the specific heat cp, and the resistance ρ of GdAuIn, GdAuMg, EuAuMg, EuAgMg, YbAuMg, YbAgMg, and LaAgMg. The measurements of the magnetization and the specific heat indicate a ferromagnetic ordering in EuAuMg (Tc ≃ 36 K) and EuAgMg (Tc ≃ 22 K). According to a very small hysteresis, EuAgMg and EuAuMg may be classified as soft ferromagnets. An antiferromagnetic ordering is present in GdAuIn (TN ≃ 12 K) and GdAuMg (TN ≃ 80.5 K). For LaAgMg and YbAgMg we find no indications for magnetic ordering, but in YbAuMg cp and M show small anomalies around 2.5 K, whose origin is yet to clarified. In all samples with magnetic order we find a large negative magnetoresistance around the respective ordering temperature. Moreover, the magnetocaloric effect is very pronounced in some of the samples. For example, when GdAuIn is magnetized under adiabatic conditions it drastically lowers its temperature. supported by the DFG through SPP 1166