Spin Glass Behavior In Rusr2gd1.5ce0.5cu2 O10-δ

The dynamics of the magnetic properties of polycrystalline polycrystalline RuSr2Gd1.5CeO.5Cu2 O10-δ (Ru-1222) have been studied by ac susceptibility and dc magnetization measurements, including relaxation and ageing studies. Ru-1222 is a reported magnetosuperconductor with Ru spins magnetic ordering at temperatures near 100 K and superconductivity in Cu-O2 planes below Tc∼40 K. The exact nature of Ru spins magnetic ordering is still being debated, and no conclusion has been reached yet. In this work, a frequency-dependent cusp was observed in Xac vs T measurements, which is interpreted as a spin glass transition. The change in the cusp position with frequency follows the Vogel-Fulcher law, which is commonly accepted to describe a spin-glass with magnetically interacting clusters. Such an interpretation is supported by thermoremanent magnetization (TRM) measurements at T=60 K. TRM relaxations are well described by a stretched exponential relation, and present significant aging effects.672204071204074Felner, I., Asaf, U., Levi, Y., Millo, O., (1997) Phys. Rev. B, 55, pp. R3374Felner, I., Asaf, U., (1998) Int. J. Mod. Phys. B, 12, p. 3220Živković, I., (2002) Phys. Rev. B, 65, p. 144420Hirai, Y., (2002) Phys. Rev. B, 65, p. 054417Escote, M.T., (2002) Phys. Rev. B, 66, p. 144503Awana, V.P.S., Ichihara, S., Karppinen, M., Yamauchi, H., (2002) Physica C, 378-381, p. 249Awana, V.P.S., (2002) J. Appl. Phys., 91, p. 8501Chen, X.H., (2001) Phys. Rev. B, 63, p. 064506Bernhard, C., (1999) Phys. Rev. B, 59, p. 14099Tallon, J.L., (1999) IEEE Trans. Appl. Supercond., 9, p. 1696Pringle, D.J., Tallon, J.L., Walker, B.G., Trodahl, H.J., (1999) Phys. Rev. B, 59, pp. R11679Fainstein, A., Winkler, E., Butera, A., Tallon, J., (1999) Phys. Rev. B, 60, pp. R12597Lynn, J.W., (2000) Phys. Rev. B, 61, pp. R14964Williams, G.V.M., Krämer, S., (2000) Phys. Rev. B, 62, p. 4132Tokunaga, Y., (2001) Phys. Rev. Lett., 86, p. 5767Takagiwa, H., Akimitsu, J., Kawano-Furukawa, H., Yoshizawa, H., (2001) J. Phys. Soc. Jpn., 70, p. 333Chmaissem, O., (2000) Phys. Rev. B, 61, p. 6401Jorgensen, J.D., (2001) Phys. Rev. B, 63, p. 054440Butera, A., Fainstein, A., Winkler, E., Tallon, J., (2001) Phys. Rev. B, 63, p. 054442Knee, C.S., Reinford, B.D., Weller, M.T., (2000) J. Mater. Chem., 10, p. 2445Awana, V.P.S., J. Low Temp. Phys., , to be publishedBeck, P.A., (1978) Prog. Mater. Sci., 23, p. 1Knitter, R.W., Kouvel, J.S., Claus, H., (1977) J. Magn. Magn. Mater., 5, p. 356Zysler, R.D., Fiorani, D., Testa, A.M., (2001) J. Magn. Magn. Mater., 224, p. 5Hurd, C.M., (1982) Contemp. Phys., 23, p. 469Ford, P.J., (1982) Contemp. Phys., 23, p. 141Mydosh, J.A., (1993) Spin Glasses: An Experimental Introduction, , Taylor & Francis, LondonEdwards, E.A., Anderson, P.W., (1975) J. Phys. F: Met. Phys., 5, p. 965Tholence, J.L., Toumier, R., (1974) J. Phys. (Paris), Colloq., 35, pp. C4-C22