Physical properties of quaternary compounds Gd₂CoAl₄T₂ (T= Si, Ge) single crystals

Abstract

We have synthesized and investigated physical properties of two new quaternary compounds Gd₂CoAl₄T₂ (T= Si, Ge) single crystals, which are isostructural to Tb₂NiAl₄Ge₂ and Er₂CoAl₄Ge₂. The most important structural feature of these materials is the anti-CaF₂-type CoAl₄T₂ slabs. These materials show metallic behavior below 300 K and there is a long-range antiferromagnetic (AFM) transition appearing at 20 and 27 K for Gd₂CoAl₄Ge₂ and Gd₂CoAl₄Si₂, respectively. Resistivity and heat capacity measurements also confirm these bulk AFM transitions. Further analysis indicates that this long-range antiferromagnetism should result from the magnetic interaction between local moments of Gd³⁺ ions.

Keywords

magnetic materials / rare earth compounds / single crystal growth

References

[1] P. C. Canfield and Z. Fisk, Growth of single crystals from metallic fluxes, Philos. Mag. B 65, 1117 (1992)

[2] M. G. Kanatzidis, R. Pöttgen, and W. Jeitschko, The metal flux: A preparative tool for the exploration of intermetallic compounds, Angew. Chem. Int. Ed. 44(43), 6996 (2005)

[3] S. Okada, Y. Yu, T. Lundström, K. Kudou, and T. Tanaka, Crystal growth and some properties of LuB₄, LuAlB₄, and Lu₂AlB₆, Jpn. J. Appl. Phys. 35(Part 1, No. 9A), 4718 (1996)

[4] S. Okada, K. Kudou, K. Iizumi, K. Kudaka, I. Higashi, and T. Lundström, Single-crystal growth and properties of CrB, Cr₃B₄, Cr₂B₃ and CrB₂ from high-temperature aluminum solutions, J. Cryst. Growth 166(1–4), 429 (1996)

[5] B. Sieve, X. Z. Chen, J. A. Cowen, P. Larson, S. D. Mahanti, and M. G. Kanatzidis, Multinary intermetallics from molten Al. Synthesis of SmNiAl₄Ge₂ and YNiAl₄Ge₂. Possible spin frustration in separated triangular Sm³⁺ layers, Chem. Mater. 11(9), 2451 (1999)

[6] X. Z. Chen, S. Sportouch, B. Sieve, P. Brazis, C. R. Kannewurf, J. A. Cowen, R. Patschke, and M. G. Kanatzidis, Exploratory synthesis with molten aluminum as a solvent and routes to multinary aluminum silicides. Sm₂Ni(NixSi_1–x)Al₄Si₆ (x= 0.18–0.27): A new silicide with a ferromagnetic transition at 17.5 K, Chem. Mater. 10(10), 3202 (1998)

[7] B. Sieve, X. Z. Chen, R. Henning, P. Brazis, C. R. Kannewurf, J. A. Schultz, and M. G. Kanatzidis, Cubic aluminum silicides RE₈Ru1₂Al₄₉Si₉ (Al_xSi_12–x) (RE= Pr, Sm) from liquid aluminum. Empty (Si,Al)₁₂ cuboctahedral clusters and assignment of the Al/Si distribution with neutron diffraction, J. Am. Chem. Soc. 123(29), 7040 (2001)

[8] B. Sieve, P. N. Trikalitis, and M. G. Kanatzidis, Quaternary germanides formed in molten aluminum: Tb₂NiAl₄Ge₂ and Ce₂NiAl_6–xGe_4–y (x~0.24, y~1.34), Z. Anorg. Allg. Chem. 628(7), 1568 (2002)

[9] G. Demchenko, J. Kónczyk, P. Demchenko, R. Gladyshevskii, W. Majzner, and L. Muratova, Quaternary alumogermanides in the Er-{Co,Ni}-Al-Ge systems, Chem. Met. Alloys 1, 254 (2008)

[10] M. E. Fisher, Relation between the specific heat and susceptibility of an antiferromagnet, Philos. Mag. 7(82), 1731 (1962)

[11] F. Canepa, M. Napoletano, M. L. Fornasini, and F. Merlo, Structure and magnetism of Gd₂Co₂Ga, Gd₂Co₂Al and Gd₁₄Co₃In_2.7, J. Alloys Compd. 345(1–2), 42 (2002)

[12] F. B. Anderson and H. B. Callen, Statistical mechanics and field-induced phase transitions of the Heisenberg antiferromagnet, Phys. Rev. 136(4A), A1068 (1964)

[13] Y. Shapira and S. Foner, Magnetic phase diagram of MnF₂ from ultrasonic and differential magnetization measurements, Phys. Rev. B 1(7), 3083 (1970)

[14] F. Keffer and H. Chow, Dynamics of the antiferromagnetic spin-flop transition, Phys. Rev. Lett. 31(17), 1061 (1973)

[15] S. N. de Medeiros, M. A. Continentino, M. T. D. Orlando, M. B. Fontes, E. M. Baggio-Saitovitch, A. Rosch, and A. Eichler, Quantum critical point in CeCo(Ge_1–xSi_x)3, Physica B 281–282, 340 (2000)

[16] M. B. Fontes, J. C. Trochez, B. Giordanengo, S. L. Budko, D. R. Sanchez, E. M. Baggio-Saitovitch, and M. A. Continentino, Electron-magnon interaction in RNiBC (R= Er, Ho, Dy, Tb, and Gd) series of compounds based on magnetoresistance measurements, Phys. Rev. B 60(9), 6781 (1999)

RIGHTS & PERMISSIONS

Higher Education Press and Springer-Verlag GmbH Germany, part of Springer Nature