Reinvestigation of long-range magnetic ordering in icosahedral Tb-Mg-Zn

Z. Islam, I. R. Fisher, J. Zarestky, P. C. Canfield, C. Stassis, and A. I. Goldman

Ames Laboratory, USDOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011.

(Received 28 January 1998)

We present results of a study of possible magnetic ordering in the icosahedral phase of Tb-Mg-Zn probed by bulk magnetization measurements and neutron diffraction. Measurements on both crushed single grains and cast polycrystalline samples of Tb-Mg-Zn were performed. Magnetization measurements on both samples reveal only a spin-glass-like transition at approximately 5.8 K. Neutron diffraction from the crushed single grains reveals only short-range magnetic ordering at low temperatures, with no evidence of the long-range magnetic ordering reported previously [Charrier, Ouladdiaf, and Schmitt, Phys. Rev. Lett. 78, 4637 (1997)]. Likewise, the cast polycrystalline samples exhibit primarily diffuse scattering at low temperature, but at least one relatively sharp diffraction peak was observed. Our results indicate that for single grain samples there is no long-range magnetic ordering and that at best, the magnetic ordering in these quasicrystalline alloys is not very robust.

Phys. Rev. B 57, R11047 (1998).