Coexisting On-center And Off-center Yb3+ Sites In Ce1-x Ybx Fe4 P12 Skutterudites

Electron-spin-resonance (ESR) measurements performed on the filled skutterudite system Ce1-x Ybx Fe4 P12 (x≲0.003) unequivocally reveal the coexistence of two Yb3+ resonances associated with sites of considerably different occupations and temperature behaviors. Detailed analysis of the ESR data suggests a scenario where the fraction of oversized (Fe2 P3) 4 cages that host Yb ions are filled with a low occupation of on-center Yb3+ sites and a highly occupied T -dependent distribution of off-center Yb3+ sites. Analysis of the Y 171 b3+ (I=1/2) isotope hyperfine splittings reveal that these two sites are associated with a low (∼1 GHz) and a high (≲ 15 GHz) rattling frequency, respectively. Our findings introduce Yb3+ in Th symmetry systems and use the Yb3+ ESR as a sensitive microscopic probe to investigate the Yb3+ ions dynamics. © 2009 The American Physical Society.805Snyder, G.J., Toberer, E.S., Complex thermoelectric materials (2008) Nature Materials, 7 (2), pp. 105-114. , DOI 10.1038/nmat2090, PII NMAT2090Nolas, G., Slack, G., (2001) Am. Sci., 89, p. 136(2007), http://jpsj.ipap.jp/journal/JPSJS-77SA.html, See, for example, the SkutteruditeYanagisawa, T., Ho, P.-C., Yuhasz, W.M., Maple, M.B., Yasumoto, Y., Watanabe, H., Nemoto, Y., Goto, T., (2008) J. Phys. Soc. Jpn., 77, p. 074607. , 10.1143/JPSJ.77.074607Goto, T., Nemoto, Y., Sakai, K., Yamaguchi, T., Akatsu, M., Yanagisawa, T., Hazama, H., Sato, H., (2004) Phys. Rev. B, 69, p. 180511. , 10.1103/PhysRevB.69.180511Lee, C.H., Hase, I., Sugawara, H., Yoshizawa, H., Sato, H., (2006) J. Phys. Soc. Jpn., 75, p. 123602. , 10.1143/JPSJ.75.123602Vining, C.B., (2008) Nature Mater., 7, p. 765. , 10.1038/nmat2271Koza, M.M., Johnson, M.R., Viennois, R., Mutka, H., Girard, L., Ravot, D., (2008) Nature Mater., 7, p. 805. , 10.1038/nmat2260Jeitschko, W., Braun, D., (1977) Acta Crystallogr., Sect.B: Struct. Crystallogr. Cryst. Chem., 33, p. 3401. , 10.1107/S056774087701108XInui, T., Tanabe, Y., Onodera, Y., (1966) Group Theory and Its Applications in Physics, , Springer, BerlinTakegahara, K., Harima, H., Yanase, A., (2001) J. Phys. Soc. Jpn., 70, p. 1190. , 10.1143/JPSJ.70.1190Abragam, A., Bleaney, B., (1970) EPR of Transition Ions, , Clarendon, OxfordNakanishi, Y., Kumagai, T., Oikawa, M., Tanizawa, T., Yoshizawa, M., Sugawara, H., Sato, H., (2007) Phys. Rev. B, 75, p. 134411. , 10.1103/PhysRevB.75.134411;Yanagisawa, T., (2007) J. Magn. Magn. Mater., 310, p. 223. , 10.1016/j.jmmm.2006.10.010;Yuhasz, W.M., Frederick, N.A., Ho, P.-C., Butch, N.P., Taylor, B.J., Sayles, T.A., Maple, M.B., Giester, G., (2005) Phys. Rev. B, 71, p. 104402. , 10.1103/PhysRevB.71.104402;Rotundu, C.R., Ingersent, K., Andraka, B., (2007) Phys. Rev. B, 75, p. 104504. , 10.1103/PhysRevB.75.104504;Yuhasz, W.M., Ho, P.-C., Sayles, T.A., Yanagisawa, T., Frederick, N.A., Maple, M.B., Rogl, P., Giester, G., (2007) J. Phys.: Condens. Matter, 19, p. 076212. , 10.1088/0953-8984/19/7/076212;Yang, C.P., Wang, H., Iwasa, K., Kohgi, M., Sugawara, H., Sato, H., Crystal field effects in CeOs4Sb12 as determined by inelastic neutron scattering (2006) Applied Physics Letters, 89 (8), p. 082508. , DOI 10.1063/1.2264336Goremychkin, E.A., Osborn, R., Bauer, E.D., Maple, M.B., Frederick, N.A., Yuhasz, W.M., Woodward, F.M., Lynn, J.W., (2004) Phys. Rev. Lett., 93, p. 157003. , 10.1103/PhysRevLett.93.157003Garcia, D.J., Garcia, F.A., Duque, J.G.S., Pagliuso, P.G., Rettori, C., Schlottmann, P., Torikachvili, M.S., Oseroff, S.B., (2008) Phys. Rev. B, 78, p. 174428. , 10.1103/PhysRevB.78.174428Meisner, G.P., Torikachvili, M.S., Yang, K.N., Maple, M.B., Guertin, R.P., (1985) J. Appl. Phys., 57, p. 3073. , 10.1063/1.335217Feher, G., Kip, A.F., (1955) Phys. Rev., 98, p. 337. , 10.1103/PhysRev.98.337;Dyson, F.J., (1955) Phys. Rev., 98, p. 349. , 10.1103/PhysRev.98.349;Pake, G.E., Purcell, E.M., (1948) Phys. Rev., 74, p. 1184. , 10.1103/PhysRev.74.1184Chock, E.P., Davidov, D., Orbach, R., Rettori, C., Tao, L.J., (1972) Phys. Rev. B, 5, p. 2735. , 10.1103/PhysRevB.5.2735Korringa, J., (1950) Physica (Amsterdam), 16, p. 601. , 10.1016/0031-8914(50)90105-4;Hasegawa, H., (1959) Prog. Theor. Phys., 21, p. 1093Rettori, C., Davidov, D., Orbach, R., Chock, E.P., Ricks, B., (1973) Phys. Rev. B, 7, p. 1. , 10.1103/PhysRevB.7.1Lea, K.R., Leask, M.J.M., Wolf, W.P., (1962) J. Phys. Chem. Solids, 23, p. 1381. , 10.1016/0022-3697(62)90192-0Farach, H.A., Strother, E.F., Poole, C.P., (1970) J. Phys. Chem. Solids, 31, p. 1491. , 10.1016/0022-3697(70)90034-XAnderson, P.W., (1954) J. Phys. Soc. Jpn., 9, p. 316. , 10.1143/JPSJ.9.316Cao, D., Bridges, F., Chesler, P., Bushart, S., Bauer, E.D., Maple, M.B., (2004) Phys. Rev. B, 70, p. 094109. , 10.1103/PhysRevB.70.094109Garcia, F.A., Garcia, D.J., Duque, J.G.S., Pagliuso, P.G., Rettori, C., Schlottmann, P., Torikachvili, M.S., Oseroff, S.B., Physica