Marian Reiffers

Mechanism of Field Induced Fermi Liquid State in Yb-Based Heavy-Fermion Compound: X-ray Absorption Spectroscopy and Nuclear Magnetic Resonance Studies of YbCo2Zn20

We have investigated the field dependences of Yb valence as well as of the magnetic properties of the heavy-fermion (HF) compound YbCo 2 Zn 20 by X-ray absorption spectroscopy, 59 Co nuclear magnet...

Effect of spin fluctuations in magnetocaloric and magnetoresistance properties of Dy10Co20Si70 alloy

Systematic investigations on the structure, magnetic, thermodynamic, magnetocaloric and magnetoresistance (MR) properties of the arc melted Dy10Co20Si70 alloy are presented. The Dy10Co20Si70 alloy crystallizes in tetragonal BaNiSn3-type DyCoSi3 (space group = I4mm; No. 107) as a major phase and CaF2-type CoSi2 (space group = Fm-3m; No. 225) and C-type Si (space group = Fd-3m; No. 227) as minor phases. The title compound exhibits multiple magnetic transitions having antiferromagnetic ordering at temperatures, viz., T1 = 10.8 K, T2 = 8.8 K and T3 = 3.3 K. The magnetic and thermodynamic studies confirm these magnetic anomalies in the compound. The large value of maximum magnetic entropy change, −ΔSMMax = 16.4 and 26.6 J/kg K for the field change ΔH of 50 and 90 kOe, respectively, observed in the compound is associated with field induced magnetic transitions. Asymmetric broadening of the magnetic entropy change peaks above the ordering temperatures resulting in significant refrigerant capacities of 361 and 86...

Point Contact Spectroscopy of the Melt-Spun Cubic TbCu5

The point contact spectra (directly proportional to the electron-quasiparticle interaction function) of heterocontacts between the cubic melt-spun TbCu5 and Cu have been investigated in a spectroscopic regime. A broad peak at 18 meV is connected with electron-phonon interaction. The observed structure in the low energy range below 11 meV has the crystal electric field origin.

Study of the electron-quasiparticle interaction in NdCu by point-contact spectroscopy

We have studied the electron-quasiparticle interaction in low symmetry rare-earth intermetallic compound NdCu with an antiferromagnetic ordering at TN=10 K by the point-contact (PC) spectroscopy. We have performed the study of NdCu−Cu heterocontacts in the near ballistic regime above and below TN. We have observed crystalline-electric-field (CEF) transition peak at }3 meV. Below TN this structure becomes complicated due to the exchange interaction and crystallographic orientation of PC. The structure above 6 meV is connected with phonons

Magnetic and Heat Capacity Study of the new Gd1-xCexNi5 Series

We have prepared a new system of Gd1−xCexNi5 polycrystalline samples with concentrations x = 0, 0.2, 0.5, and 0.8 in order to study the influence of different rare-earths substitutions on the ground state connected with spin fluctuations. GdNi5 is a ferromagnetic compound with TC = 31.8 K and CeNi5 is a well-known spin fluctuation compound without magnetic ordering down to the lowest temperatures. X-ray diffraction study confirms the hexagonal crystal structure and the single phase samples. Magnetic properties (M(T ),M(B)) show that an increasing content of Ce depresses the transition temperature, TC, down to 4.9 K for x = 0.8. The heat capacity measurements confirmed these results.

NMR Investigation of Pressure Effect on Intermediate Valence Compound SmB 6

Kohei Nishiyama1, Takeshi Mito1, Gabriel Pristas1,2, Yukiko Hara1, Takehide Koyama1, Koichi Ueda1, Takao Kohara1, Yuichi Akahama1, Slavomir Gabani2, Marian Reiffers2, Karol Flachbart2, Hideto Fukazawa3, Yoh Kohori3, Nao Takeshita4, and Natalia Shitsevalova5 1Graduate School of Material Science, University of Hyogo, Hyogo 678-1297, Japan 2Institute of Experimental Physics, Slovak Academy of Science, 04001 Kosice, Slovakia 3Graduate School of Science, Chiba University, Chiba 263-8522, Japan 4National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8562, Japan 5Institute for Problem of Material Science, National Academy of Science of Ukraine, 03680 Kiev, Ukraine E-mail: mito@sci.u-hyogo.ac.jp

Heat capacity and point-contact spectra of the melt-spun cubic RECu5 compounds (RE – heavy rare earths)

Heat capacity measurements of the cubic intermetallic RECu5 (RE – heavy rare earths) compounds have been performed in the applied magnetic field up to 9 T and in the temperature range from 0.4 to300 K. The pollycrystalline samples have been prepared in ribbon shape by melt-spinning and subsequent annealing for stabilisation of the cubic phase. We have first observed the phase transitions into the magnetic ordered states in TmCu5 (1.3 K), HoCu5 (3 K) and ErCu5 (1.6 K).

Point-contact spectroscopy of the electron–quasiparticle interaction in Ce1−xNdxNi5

Abstract We report on the study of the modification of the electron–quasiparticle interaction (EQI) function in Stoner enhanced paramagnet CeNi 5 when magnetic Nd-ions are substituting Ce-ions, using point-contact (PC) spectroscopy. The intensity of the spin fluctuations peak at ∼2.5 meV in CeNi 5 decreases with increasing Nd content and it vanishes for x =0.5. The CEF peak from Nd-ions arises at x =0.5, in the magnetically ordered state.

Influence of spin fluctuations on van Vleck paramagnetism in the electron–quasiparticle interaction function of Pr1−xCexNi5 system

Abstract We report on the study of the modification of crystalline electric field (CEF) energy scheme of van Vleck paramagnet PrNi 5 when Ce-ions are substituting Pr-ions, using point-contact (PC) spectroscopy. The intensity of the main CEF peak at 4 meV in PrNi 5 is decreasing, its position is shifted to higher energy with increasing Ce content, and it disappears only for x =1 while the peak at ∼2.5 meV connected with spin fluctuations disappears for x =0.8.

The study of CEF modification in Pr1 − xNdxNi5 by point-contact spectroscopy

Abstract We report the study of the modification of crystalline electric field (CEF) energy level scheme in Van Vleck paramagnet PrNi 5 when Pr 3+ ions are substituted by magnetic Nd 3+ ions using point-contact spectroscopy. We have observed two peaks, one at ∼1.5 meV and other at ∼4 meV, associated with CEF transitions. The peak at 1.5 meV does not appear in PrNi 5 compound and is a consequence of the now allowed transition from the ground to the first excited level when introducing Nd 3+ ions.