Simplifying strong electronic correlations in uranium: Localized uranium heavy-fermionUM2Zn20(M

Abstract

The physical properties including magnetic susceptibility, magnetization, specific heat, and dynamic susceptibility Љ͑E͒ are reported for single crystals of the cubic UM 2 Zn 20 ͑M=Co,Rh͒ materials. Maxima in the thermodynamic data at T max ϳ 10 K for both compounds and a broad peak in Љ͑E͒ at 5 K in UCo 2 Zn 20 of width ⌫ = 5 meV indicate a heavy-fermion state characterized by a Kondo temperature T K ϳ 20-30 K arising from weak hybridization of f-and conduction-electron states. Anderson impurity model fits to the data in the Kondo limit including crystalline electric-field effects corroborate an ionic-like uranium electronic configuration in UM 2 Zn 20 .

Physical properties of GdFe2(AlxZnNi1, Jia2, Samolyuk3 et al. 2011Phys. Rev. B191150View full textAdd to dashboardCite

“…Of specific interest, intermetallic compounds in the vicinity of Stoner limit 1 exhibit exotic magnetic properties, such as nearly or weakly ferromagnetic Fermi liquid behavior, due to their strongly correlated d electrons. Particular attention has been paid to those systems containing both 4f local moments and highly correlated conduction electrons due to the rich phases result from the interactions between 4f and d electrons; among such materials, the RFe 2 Zn 20 compounds, which belong to the large RT 2 Zn 20 (R=Rare Earth elements, Y and U; T=Fe, Co, Ni, Ru, Rh, Os, Ir and Pt) series [2][3][4][5][6][7] , provide an ideal experimental platform, not only because they show various magnetic properties but also because they can be easily substituted on a number of unique crystallographic sites 3,4,[8][9][10] . RT 2 Zn 20 crystallizes in Fd3m space group, the nearest and next nearest neighbors of R and T atoms are all Zn.…”

Thermal and magnetic properties of the low-temperature antiferromagnetCe4Pt12Sn25

“…Large U-U distance d U-U ϳ 6 Å in UM 2 Zn 20 ͑M =Co,Rh͒ family of materials reduces the overlap between the 5f-electron wave functions, allowing for observation of sharp crystal electric fields ͑CEFs͒, a situation very rare in U compounds. 23 At the same time, this U-U separation resulted in a good description of the system within a Kondo 25 Previous specific-heat, resistivity, and ac-susceptibility measurements uncovered a phase transition at 0.18 K. 25 However, the origin of the transition was not identified. In this paper, we report the low-temperature specific-heat ͑C͒ and magnetization ͑M͒ measurements in magnetic field.…”

Crystal structure of UT2Zn20 (T=Fe, Co, Ru, Rh, and Ir) phases

“…The available literature data on the UT 2 Zn 20 compounds report on interesting physical properties, which are closely related to their crystal structures [1][2][3][4][5][6][7]. One may expect that intentional changes in the composition of these alloys would yield some significant modifications in their physical behaviour.…”

“…The primary findings made for the phases with T = Co, Rh and Ir [1][2][3] have stimulated further comprehensive investigations on high-quality single crystals of these ternaries and also those with T = Fe and Ru [4][5][6][7]. Though all the hitherto identified UT 2 Zn 20 compounds were claimed to form with a cubic unit cell of the Mg 3 Cr 2 Al 18 type, up to date no precise information on their crystal structures has been available in the literature.…”

“…The uranium compounds UT 2 Zn 20 (T = d-electron transition metal) have recently been reported to exhibit a variety of intriguing physical phenomena, which arise due to strong electronic correlations [1][2][3][4][5][6][7]. The primary findings made for the phases with T = Co, Rh and Ir [1][2][3] have stimulated further comprehensive investigations on high-quality single crystals of these ternaries and also those with T = Fe and Ru [4][5][6][7].…”