Release of the Magnetic Frustration in a Quasi-Kagome Antiferromagnet YbAgGe by Au Substitution

We report on magnetic and transport properties of YbAg1-xAuxGe (x = 0, 0.03, 0.07, 0.11) single crystals by means of specific heat, electrical resistivity, and magnetization measurements. In YbAgGe, Yb atoms form a quasi-kagome lattice in the hexagonal c-plane. This compound undergoes two magnetic phase transitions at TM1 = 0.8 K (second order) and TM2 = 0.65 K (first order). The magnetic frustration effect manifests itself in a pronounced tail of the specific heat in the temperature range up to 2TM1. With increasing x, TM2 disappears at a low level of x=0.03 and TM1 gradually increases. We found that TM1 increases up to 1.3 K for x = 0.11, while the Kondo temperature rises. Furthermore, the ratio of the absolute value of paramagnetic Curie temperature p and TM1, p/TM1 decreases with x. These observations suggest that the magnetic frustration in the Yb sublattice is released by the atomic disorder in the nonmagnetic Ag-Ge sublattice.

[1]  T. Takabatake,et al.  Geometrical frustration versus magnetic order in the heavy-fermion antiferromagnet YbAgGe under high pressure , 2010 .

[2]  M. Kim,et al.  Yb2Pt2Pb: Magnetic frustration in the Shastry-Sutherland lattice , 2008, 0801.4875.

[3]  T. Takabatake,et al.  Pressure-Induced Release of Magnetic Frustration in a Quasi-Kagome Antiferromagnet YbAgGe(Condensed matter: electronic structure and electrical, magnetic, and optical properties) , 2008 .

[4]  J. Thompson,et al.  Correlation between magnetic frustration and electrical conductivity inRInCu4compounds(R=Gd−Tm) , 2006 .

[5]  E. Ressouche,et al.  An inelastic neutron scattering study of single-crystal heavy-fermion YbAgGe , 2004, cond-mat/0410736.

[6]  T. Sakakibara,et al.  Successive magnetic transitions in a frustrated compound YbAgGe , 2004 .

[7]  P. Canfield,et al.  Magnetic field induced non-Fermi-liquid behavior in YbAgGe single crystals , 2003, cond-mat/0308517.

[8]  K. Katoh,et al.  Magnetic properties of YbTGe (T=Rh, Cu, Ag) , 2004 .

[9]  R. Cava,et al.  The effect of gallium substitution for iron on the magnetic properties of hydronium iron jarosite , 1999 .

[10]  G. Ehlers,et al.  Geometrically frustrated magnetic structures of the heavy-fermion compound CePdAl studied by powder neutron diffraction , 1996 .

[11]  R. Pöttgen,et al.  Ternary germanides LnAgGe (Ln = Y, Sm, GdLu) with ordered Fe2P-type structure , 1996 .

[12]  H. Mitamura,et al.  Faraday Force Magnetometer for High-Sensitivity Magnetization Measurements at Very Low Temperatures and High Fields , 1994 .

[13]  Arthur P. Ramirez,et al.  Strongly Geometrically Frustrated Magnets , 1994 .

[14]  N. Sato,et al.  A new dense Kondo system: CeyLa1−y Ge2. Resistivity, specific heat, and susceptibility studies , 1985 .