Low-temperature thermal and high-pressure studies of CePd and

Abstract

The anomalous properties of the Kondo lattice are compared with the well behaved Kondo system, CePd. The low-temperature thermal expansion of CePd is in agreement with previous heat capacity data, showing a ferromagnetic transition at and a second transition at 3.5 K probably due to reorientation of the magnetic moments. The Grüneisen factor, calculated from thermal-expansion and heat capacity is , the same as the Grüneisen factor calculated from the pressure dependence and comparable to a previous measurement of . Thermal expansion measurements (in fields of up to 8 T) and ac susceptibility measurements (under pressures of up to 7.33 kbar) have been made on in the temperature range 1.6-40 K. The zero-pressure ac susceptibility measurements confirm that there is an antiferromagnetic transition at , as previously reported. The magnetic contribution to the linear thermal-expansion coefficient of polycrystalline in zero magnetic field has a maximum value near 17 K and becomes small by 29 K. There is no peak in at the Néel temperature. The Néel temperature is found to decrease under pressure at the rate of , which indicates that is a magnetic Kondo lattice (with ) on the right-hand side of the Doniach diagram.

Electronic structure studies of CeAgSb2

“…Ce 6p states were added to increase the quality of the basis set. The spatial extension of the basis orbitals, controlled by a confining potential (r/r 0 ) 4 , was optimized to minimize the total energy. The self-consistent potentials were carried out on a k mesh of 18 k points in each direction of the Brillouin zone, which corresponds to 550 k points in the irreducible zone.…”

“…The temperature-dependent resistivity of CeAgSb 2 is typical of a Kondo lattice system. Preliminary inelastic neutron scattering measurements indicate a Kondo temperatur T K between 60 and 80K [4]. The magnetoresistence of CeAgSb 2 is either positive or negative, depending on the temperature and orientation of the applied field.…”

“…Sologub et al [1] reported this compound has weak ferromagnetic oder in polycrystalline samples with a net ferromagnetic moment of 0.15 µ B /Ce at 5 K. Several different groups investigated the magnetic properties of CeAgSb 2 with conflicing results for the magnetic ground state. [2,3,4]. In particular, for single crystal smaples, the magentization of CeAgSb 2 is anisotropic [5].…”

Magnetization and electrical-transport investigation of the dense Kondo systemCeAgSb2

“…3,12 Several different groups have investigated the magnetic properties of CeAgSb 2 with conflicting results for the interpretation of the magnetic ground state. 6,7,[13][14][15][16] For instance, Muro et al 6 suggested a ferrimagnetic ground state in polycrystalline samples with a spin-flip field of about 1.3 T. However, this result disagrees with muon spin rotation ͑SR͒ measurements where spectra in both the ordered state and paramagnetic state indicate a single crystallographic and magnetic muon site. 16 Nevertheless, in accordance with SR measurements, 16 it is very difficult in polycrystalline samples to differentiate between a simple ferromagnetic structure and ©2005 The American Physical Society 104428-1 a complex antiferromagnetic structure with a resultant ferromagnetic component.…”

Neutron scattering and thermal studies of the Ni-incorporatedCeSbNixsystem

“…It is generally observed that ␣ mag (T) exhibits a peak, similar to that observed in the heat capacity, at the magnetic ordering temperature. 27 Figure 6 shows ␣ 4 f (T)a sa function of temperature for CeSbNi x alloys. ␣ 4 f (T) of CeSb ͑in zero field͒ exhibits a sharp peak at 15.4 K, followed by a second broad peak at 12.9 K. The sharp peak in ␣ 4 f (T)i s due to the first-order phase transition from the paramagnetic to antiferroparamagnetic ͑AFP, kϭ2/3,↑᭺↓; the open circle shows the position of the paramagnetic plane͒ phase.…”