The most interesting features in the magnetic behaviour of the mixed crystal system (Fe, Mnl-,)W04 are that the end members, although possessing the same crystal structure, have different magnetic structures and that the exchange interactions involved in the magnetic ordering are quite different. Les rksultats sont discutks sur la base d'un modkle pour un cristal magnktiquement dksordonnk. interaction a kt6 ktudik en utilisant la diffraction de neutrons et la spectroscopie Mossbauer.
#STANLEY PENC PLUS#
Les caractkristiques les plus intkressantes dans le comportement magnktique du systkme de cristaux mixtes (Fe, Mn I-~)WO~ proviennent du fait que, bien que posskdant la meme structure cristallographique, les composks extremes ont des structures magnktiques diffkrentes et que les interactions d'kchange impliqukes dans I'ordre magnktique sont trks diffkrentes. The hyperfine field at the Sn site in Pd2TbSn is about 50 kOe but is only about 10 kOe in Pd2DySn at 4.2 K. The Tb- and Dy-containing compounds order antiferromagnetically with Néel temperatures of 9 and 15 K, respectively, while Er- and Ho-containing compounds are paramagnetic down to 1.4 K. The susceptibility of Yb3+ ions at low temperatures is also reduced from the free-ion value due to the crystalline electric field interaction. Analysis of the magnetic susceptibility data in terms of crystalline electric fields shows that the ground state of the Tm3+ ion is nonmagnetic which, therefore, does not affect the superconducting state.
The magnetic susceptibility of Pd2TmSn and Pd2YbSn deviates from the Curie-Weiss behavior at low temperatures indicating that crystalline electric field effects are appreciable. The Tm and Yb compounds in this series along with Lu, Sc, and Y compounds are superconducting. Magnetic susceptibility and 119Sn Mössbauer studies have been carried out on a new series of rare-earth-containing Heusler alloys having the formula Pd2RSn (R=Tb–Yb).