Hydrostatic pressure study of pure and dopedLa1−xRxAgSb2

M. S. Torikachvili

¹

,

Sergey L. Bud’ko

²

,

Stephanie Law

³

et al.

Abstract

The intermetallic compound LaAgSb 2 displays two charge-density-wave (CDW) transitions, which were detected with measurements of electrical resistivity (!), magnetic susceptibility, and X-ray scattering; the upper transition takes place at T 1 ! 210 K, and it is accompanied by a large anomaly in !(T), whereas the lower transition is marked by a much more subtle anomaly at T 2 ! 185 K. We studied the effect of hydrostatic pressure (P) on the formation of the upper CDW state in pure and doped La 1-x R x AgSb 2 (R = Ce, Nd) compounds, by means of measurements of !(T) for P ! 23 kbar. We found that the hydrostatic pressure, as well as the chemical pressure introduced by the partial substitution of the smaller Ce and Nd ions for La, result in the suppression of the CDW ground state, e.g. the reduction of the ordering temperature T 1 . The values of dT 1 /dP are ! 2-4 times higher for the Ce-doped samples as compared to pure LaAgSb 2 , or even La 0.75 Nd 0.25 AgSb 2 Nd-doped with a comparable T 1 (P=0). This increased sensitivity to pressure may be due to increasing Ce-hybridization under pressure. The magnetic ordering temperature of the cerium-doped compounds is also reduced by pressure, and the high pressure behavior of the Ce-doped samples is dominated by Kondo impurity scattering.PACS Nos. 62.50.+p, 71.45.Lr, 75.20.Hr 2

Charge density wave in layeredLa1−xCexSb2

“…In LaAgSb 2 , the CDW was observed in thermodynamic and transport measurements, in x-ray scattering experiments, and studied as a function of substitution [20][21][22]. Substitution of La with Ce in La 1−x Ce x AgSb 2 gives a suppression of the CDW and a broadening of the observed features in resistivity [23,24]. Here we find a kink in the resistivity of LaSb 2 above room temperature evidencing CDW order in this compound.…”

Tuning of charge density wave transitions in LaAuxSb2 by pressure and Au stoichiometry

“…Effects of rare-earth substitution [24,25] and hydrostatic pressure [24,26] on the temperature of the higher CDW transition, T CDW1 were studied. The observed suppression of the T CDW1 was explained as a combination of increase of the threedimensional character of LaAgSb 2 (decrease of c/a value) and the substitution-related disorder.…”

“…The observed suppression of the T CDW1 was explained as a combination of increase of the threedimensional character of LaAgSb 2 (decrease of c/a value) and the substitution-related disorder. It was also recognized that the pressure response of T CDW1 could be affected by local moment magnetism as well as hybridization due to rare-earth (R = Ce, Pr, Nd,...) substitution in (La 1−x R x )AgSb 2 [26].…”

Chemical and hydrostatic pressure effect on charge density waves of SmNiC2

“…However, there has been little understanding of - Pressure is an important parameter for the control of not only the CDW phase but also magnetism or superconductivity. In particular, there have been many pressure experiments for transition metal chalcogenides [15][16][17] and some rare earth compounds [18][19][20], including SmNiC 2 [8], in order to investigate the competition between the CDW and magnetism or superconductivity. However, there has been little theoretical analysis to verify the competition mechanism and pressure dependent order parameter changes.…”