Ultrasonic study of the hidden order and heavy-fermion state in URu₂Si₂with hydrostatic pressure, Rh-doping, and high magnetic fields

Abstract

To cite this article: Tatsuya Yanagisawa (2014) Ultrasonic study of the hidden order and heavyfermion state in URu 2 Si 2 with hydrostatic pressure, Rh-doping, and high magnetic fields, Philosophical Magazine, 94:32-33, 3775-3788, This paper reports recent progress of ultrasonic measurements on URu 2 Si 2 , including ultrasonic measurements under hydrostatic pressure, in pulsed magnetic fields, and the effect of Rh-substitution. The observed changes of the elastic responses shed light on the orthorhombic-lattice instability with 3 -symmetry existing within the hidden order and the hybridized 5 f -electron states of URu 2 Si 2 .

Electronic properties of a heavy-fermion U(Ru0.92Rh0.08)2Si2 single cr

“…The q III propagation vector is distinctly different from the q I = (1 0 0) characterizing the parasitic SMAF 13,34,35 (Fe or Os doping or pressure induced LMAF) or q II = (0.6 0 0) propagation vector of the very high field spin density wave (SDW) observed in pure URu 2 Si 2 10 . The long-range character of the q III AF order appears at slightly higher Rh concentrations 11,12 , not reached in our 8 % Rh-doped crystal. Thus we have destroyed the HO and superconductivity with Rh substitution allowing a pure heavy Fermi liquid to remain.…”

“…However, and most important, our 8% Rhsubstituted crystal does not exhibit any sort of phase transition or long-range order down to 0.4 K. Instead, according to our neutron scattering experiments, it displays short-range order of the q I I I = ( [10]. The long-range character of the q I I I AF order appears at slightly higher Rh concentrations [11,12] not reached in our 8%-Rh-doped crystal. Thus we have destroyed the HO and superconductivity with Rh substitution, allowing a pure heavy Fermi liquid to remain.…”

“…Our preliminary indications of magnetic fluctuations in the inelastic neutron scattering point to a precursor of the higher Rh concentration magnetic order found in Refs. [11] and [12]. Finally we note the difference between Rh tuning (leading to magnetic order with q I I I ), pressure tuning (magnetic order with q I ), and field tuning (characterized by q I I ) of the HO behavior of URu 2 Si 2 towards LMAF-an intriguing problem for theoretical consideration.…”

“…% substitution of various transition metals (Re, Rh, Fe, Os, Tc) for Ru destroy the SC and induce magnetic states. The doping weakens the HO state and transforms it to long-range magnetic order that is for different dopants different (the AF order with q I = (1 0 0) being the most frequent one) [11][12][13][14][15][16][17][18][19]. In some * prokes@helmholtz-berlin.de cases the crossover between the HO state and dopant-induced long-range magnetic order is smooth (as in the case of Fe doping); in other cases a gap between the two ground states exists (the case of Rh) [11,20], preceded by a tiny concentration region where the LMAF phase seems to inhomogeneously coexist.…”

Field-induced phases in a heavy-fermion U(Ru0.92Rh0.08)2Si2 single crystal

“…Single crystals of higher quality with a higher residual electrical resistivity show as a rule smaller dipolar U moments. These moments, however, can develop either under pressure or with light doping of different dopants (Re, Rh, Fe, Os, Tc) 3,7,[11][12][13][14][15] . A common effect is that the HO and SC states are suppressed fairly quickly and new types of a magnetic order appear.…”