Magnetoresistivity anisotropy in CeRu2Si2 and derived alloys (original) (raw)

Magnetic susceptibility of CeRu3Si2 and a scaling effect in mixed-valence compounds

Physica B: Condensed Matter, 2003

To investigate the mixed-valence (MV) state in CeRu 3 Si 2 , we measured the magnetic susceptibility wðTÞ in the temperature range 8-300 K. The magnetic susceptibility is constant below 100 K, and slightly increases with increasing temperature. We estimated the spin fluctuation temperature T sf by plotting wðTÞT=C against T; where C is the Curie constant of a Ce 3+ ion. CeRu 3 Si 2 is found to be a typical MV system, indicating that wðTÞT=C is a function of T=T sf : This scaling relation is applied to the other MV compounds such as CeSn 3 .

Magnetovolume study of the metamagnetic transition of CeRu2Si2 below 1 K

Physica B: Condensed Matter, 1991

We report magnetostriction and thermal-expansion measurements on a single-crystalline sample of the heavy-fermion compound CeRu,Si, in the temperature interval 0.1 < T < 1.3 K and in fields along the tetragonal axis up to 12 T, in order to study the metamagnetic-like transition. The width of the field-induced transition (at -7.7T) as observed by magnetostriction narrows on cooling and seems to remain finite at T = 0 K indicating that the transition remains continuous for the present sample.

Magnetic properties of some cerium-based alloys

Journal of Alloys and Compounds, 1994

We report the results for d.c. electrical resistivity (1.5-300 K), low temperature heat capacity (2-25 K) and magnetic susceptibility (5-300 K) of CeSil.sCuo.2, CeSil.sNio.2, CeSiL6Coo.4, CeSil.sNio.5 and CemGe~.4Nio.6. The first two alloys have the ct-ThSi2 type structure of the parent CeSi2 while the latter crystallize in the hexagonal AIB2 type. The influence of both the Ruderman-Kittel-Kasuya-Yoshida exchange interaction and the single-ion Kondo exchange interaction are observed in CeSi~.sCuo.2 and CeSi~.sNio.2. CeSil.6Coo.4 is non-magnetic but magnetic ordering takes place in CeSi~.sNio.5 near 3 K. The data indicate that the crystal field splitting in the alloy containing germanium may be relatively smaller.

Magnetic instabilities in CeRu2Si2 compounds

Physica B: Condensed Matter, 1999

Neutron scattering experiments were recently performed in compounds of the CeRu Si family. The topic addressed is the proximity of magnetic instabilities. The first one is the proximity of a ¹"0 K quantum phase transition experimentally achieved with lanthanum doping. The second kind of instability is linked to the competition between antiferromagnetic and ferromagnetic interactions in these materials. The pseudo-metamagnetic transition of CeRu Si and the occurrence of an antiferromagnetic phase in the ferromagnetic compound CeRu Ge were studied. Comparisons with macroscopic measurements are made using a simple analysis of the data.

ac susceptibility and static magnetization measurements of CeRu 2 Si 2 at small magnetic fields and ultralow temperatures

Physical Review B, 2003

The magnetic properties of CeRu2Si2 at microkelvin temperatures (down to 170 µK) and ultra small magnetic fields (0.02 ∼ 6.21 mT) are investigated experimentally for the first time. The simultaneously measured ac susceptibility and static magnetization show neither evidence of the magnetic ordering, superconductivity down to the lowest temperatures nor conventional Landau Fermi-Liquid behavior. The results imply the magnetic transition temperature in undoped CeRu2Si2 is very close to absolute 0 K. The possibility for proximity of CeRu2Si2 to the quantum critical point without any doping is discussed.

Magnetic form factor in CeRu2Si2 on crossing its metamagnetic transition

The magnetic form factor of the heavy fermion compound CeRu2Si2 was measured by polarized neutron diffraction in the Pauli paramagnetic phase and above the metamagnetic transition. The magnetization density is characteristic of 4f electrons in both phases with an almost pure |5/2,5/2⟩ ground-state wavefunction. The only field effect observed in this experiment corresponds to a nonlinear variation of the magnetization of the 4f electrons.

Magnetic behavior near the boundary of4fdelocalization in ferromagnetic CeRu2Ge2and paramagnetic CeRu2Si2observed by CeM4,5XAS and XMCD

Physical Review B, 2012

X-ray absorption (XAS) and its magnetic circular dichroism (XMCD) were measured at the Ce M 4,5 absorption edges of ferromagnetic CeRu 2 Ge 2 and paramagnetic CeRu 2 Si 2 : both compounds are considered to be located near the boundary of delocalization of Ce 4f electrons. While the XAS line shape varies clearly reflecting the variation in the 4f delocalization, the line-shape variation in XMCD is hardly discernible under various conditions of temperature and magnetic field. The XAS line-shape variation can be explained as effects of the variations in the 4f occupation number and in the ratio of J = 7/2 states in the ground states, both of which are closely related to the 4f delocalization. The 4f delocalization also causes a decrease in the ratio of the orbital magnetic moment to the spin magnetic moment. The magnetic-field dependence of XAS suggests that the Ce 4f electrons retain a delocalized character across the metamagnetic transition in CeRu 2 Si 2 .

Metamagnetic-like transition in CeRu2Si2?

Journal of Low Temperature Physics, 1987

Extensive magnetization and magnetoresistivity experiments on CeRueSi 2 are described, with special emphasis on the metamagnetic-like transition that occurs' at H * = 80 kOe. By contrast to the low-fieM susceptibility, the differential susceptibility at H* almost diverges at T ~ O. It is suggested that high magnetic fields (H > H*) restore a situation where the interactions between particles have collapsed. Comparison is made with other well-known examples: TiBe2, UPt3, TmSe, and 3He.