Evidence for the Single-Site Quadrupolar Kondo Effect in the Dilute Non-Kramers System Y1−xPrxIr

Abstract

Acoustic signatures of the single-site quadrupolar Kondo effect in Y0.966Pr0.034Ir2Zn20 are presented. The elastic constant (C11 − C12)/2, corresponding to the Γ3(E)-symmetry electricquadrupolar response, reveals a logarithmic temperature dependence of the quadrupolar susceptibility in the low-magnetic-field region below ∼0.3 K. Furthermore, the Curie-type divergence of the elastic constant down to ∼1 K indicates that the Pr ions in this diluted system have a non-Kramers ground-state doublet. These observations evidence the single-site quadrupolar Kondo effect, as previously suggested based on specific-heat and electrical resistivity data.

Unconventional non-Fermi liquid properties of two-channel Anderson impurities system

“…This is also consistent with the following experimental fact. Indeed, the T dependence of ultrasound dispersion in the same system shows that the width of the energy splitting of Γ 3 states, 3 D G , is about 0.048K [27], which is sufficiently lower than the characteristic temperature scale characterising the non-Fermi liquid state: T 0 = 0.3K [17], above which the T dependence of the electrical resistivity deviates from T behavior. It is obvious that if 3 D G is larger than T 0 , the non-Fermi liquid temperature dependence disappears.…”

“…First of all, a f ˜and E 0 ˜are independent of c imp . This is because equations determining these quantities, equations ( 26) and (27), are transformed to equations (48) and (47) in [10], respectively, considering that V c V imp = ˜and the relation equation ( 22) holds. Since a f ˜and E 0 ˜are independent of c imp , the coefficient A imp (equation ( 30)) is proportional to c imp while the coefficient A latt (equation ( 31)) is proportional to c imp 2 [ ] , as mentioned above.…”

Effects of Magnetic Field on the Nonmagnetic Doublet Ground State in PrMgNi4

“…Recently, the coexistence of quadrupole order and superconductivity was observed in PrT 2 Zn 20 (T = Ir, Rh) and PrT 2 Al 20 (T = Ti, V), which suggests that the superconducting pair could be mediated by quadrupole fluctuations [8]. Furthermore, non-Fermi liquid (NFL) behaviors were observed not only in PrIr 2 Zn 20 [9] and PrRh 2 Zn 20 [10] but also in the diluted Pr system Y(Pr)Ir 2 Zn 20 [11,13], indicating a possible manifestation of the quadrupole Kondo effect [14]. As described above, the intensive works on the 4 f 2 systems have revealed a wide variety of phenomena due to the interactions between the multipolar degrees of freedom of the 4 f 2 electrons and conduction electrons.…”

Magnetic Properties of a Diluted Nd System Y1−xNdxCo2Zn20 for x = 0.20 with a \(\Gamma _{6}\) Doublet Ground State

“…Furthermore, non-Fermi liquid (NFL) behaviors of the magnetic specific heat C m and electrical resistivity ρ were observed in moderately wide temperature range of T > T Q [11,12]. In the diluted Pr system of Y 1−x Pr x Ir 2 Zn 20 , NFL behaviors of C m , elastic constant, and ρ were observed, suggesting manifestation of the two-channel Kondo effect [13][14][15].…”