Magnetic Structures Of The Anisotropic Intermetallic Compounds Er 2coga8 And Tm2 Coga8

Two members of the isostructural R2 CoGa8 intermetallic series, Er2CoGa8 and Tm2 CoGa8, have been studied by powder neutron diffraction. Antiferromagnetic ordering of the rare-earth sublattices was confirmed to occur at 3.0 K and 2.0 K, respectively. Furthermore, determination of the critical exponent showed Er2 CoGa8 to adopt a three-dimensional universality class. In spite of a common magnetic easy axis and similar structural characteristics, the antiferromagnetic structures were found to be different for the erbium- and thulium-based compounds. The corresponding magnetic space groups were determined to be P2a mm m′ and PC mmm. The difference in magnetic structures is discussed based on crystal electric field effects that are known to be prevalent in such materials. © 2010 The American Physical Society.8210Chen, G., Ohara, S., Hedo, M., Uwatoko, Y., Saito, K., Sorai, M., Sakamoto, I., (2002) J. Phys. Soc. Jpn., 71, p. 2836. , 10.1143/JPSJ.71.2836Nicklas, M., Sidorov, V.A., Borges, H.A., Pagliuso, P.G., Petrovic, C., Fisk, Z., Sarrao, J.L., Thompson, J.D., (2003) Phys. Rev. B, 67, p. 020506. , 10.1103/PhysRevB.67.020506Sugitani, I., (2006) J. Phys. Soc. Jpn., 75, p. 043703. , 10.1143/JPSJ.75.043703Kimura, N., Muro, Y., Aoki, H., (2007) J. Phys. Soc. Jpn., 76, p. 051010. , 10.1143/JPSJ.76.051010Bauer, E., Kaldarar, H., Prokofiev, A., Royanian, E., Amato, A., Sereni, J., Bramer-Escamilla, W., Bonalde, I., (2007) J. Phys. Soc. Jpn., 76, p. 051009. , 10.1143/JPSJ.76.051009Pagliuso, P.G., (2006) J. Appl. Phys., 99, pp. 08P703. , 10.1063/1.2176109Settai, R., Takeuchi, T., Onuki, Y., (2007) J. Phys. Soc. Jpn., 76, p. 051003. , 10.1143/JPSJ.76.051003Joshi, D.A., Tomy, C.V., Malik, S.K., (2007) J. Phys.: Condens. Matter, 19, p. 136216. , 10.1088/0953-8984/19/13/136216Steglich, F., Aarts, J., Bredl, C.D., Lieke, W., Meschede, D., Franz, W., Schafer, H., (1979) Phys. Rev. Lett., 43, p. 1892. , 10.1103/PhysRevLett.43.1892Szytula, A., Leciejewicz, J., (1994) Handbook of Crystal Structures and Magnetic Properties of Rare Earth Intermetallics, , CRC Press, Boca RatonJoshi, D.A., Nagalakshmi, R., Dhar, S.K., Thamizhavel, A., (2008) Phys. Rev. B, 77, p. 174420. , 10.1103/PhysRevB.77.174420Joshi, D.A., Nigam, A.K., Dhar, S.K., Thamizhavel, A., (2009) Phys. Rev. B, 80, p. 054414. , 10.1103/PhysRevB.80.054414Adriano, C., Mendonca-Ferreira, L., Bittar, E.M., Pagliuso, P.G., (2008) J. Appl. Phys., 103, pp. 07B712. , 10.1063/1.2830801Kaczorowski, D., Pikul, A.P., Gnida, D., Tran, V.H., (2009) Phys. Rev. Lett., 103, p. 027003. , 10.1103/PhysRevLett.103.027003Adriano, C., Giles, C., Coelho, L.N., Pagliuso, P.G., (2009) Physica B, 404, p. 3289. , 10.1016/j.physb.2009.07.127Fisk, Z., Remeika, J.P., (1989) Handbook on the Physics and Chemistry of Rare Earths, 12. , Elsevier, New Yorkhttp://www.isis.rl.ac.uk/Rodríguez-Carvajal, J., (1993) Physica B, 192, p. 55. , 10.1016/0921-4526(93)90108-ICollins, M.F., (1989) Magnetic Critical Scattering, , Oxford University Press, OxfordWallace, W.E., (1973) Rare Earth Intermetallics, , Academic Press, New YorkMiller, S.C., Love, W.F., (1967) Tables of Irreducible Representations of Space Groups and Co-Representations of Magnetic Space Groups, , Preutt Press, Boulderhttp://www.mcphase.deLitvin, D.B., (2008) Acta Crystallogr., Sect. A: Found. Crystallogr., 64, p. 419. , 10.1107/S010876730800768XRoutsi, C.D., Yakinthos, J.K., Gamari-Seale, E., (1992) J. Magn. Magn. Mater., 116, p. 397. , 10.1016/0304-8853(92)90121-4Goremychkin, E.A., Osborn, R., Rainford, B.D., MacAluso, R.T., Adroja, D.T., Koza, M., (2008) Nat. Phys., 4, p. 766. , 10.1038/nphys1028Bao, W., Pagliuso, P.G., Sarrao, J.L., Thompson, J.D., Fisk, Z., Lynn, J.W., (2001) Phys. Rev. B, 64, p. 020401. , 10.1103/PhysRevB.64.020401Morin, P., Giraud, M., Regnault, P.L., Roudaut, E., Czopnik, A., (1987) J. Magn. Magn. Mater., 66, p. 345. , 10.1016/0304-8853(87)90168-