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A single crystal of rare earth intermetallic compound Dy5Si2Ge2 (Orthorhombic, Space group Pnma) has been prepared by Czochralski method. Magnetization of Dy5Si2Ge2 single crystal has been measured with magnetic field applied (i) along b axis and (ii) parallel to ac plane. Although a same Neel temperature (TN) of ∼55 K is obtained when 50 Oe field is applied along b axis and in ac plane, the magnitude of magnetization is substantially different. This TN value is close to the antiferromagnetic ordering temperature of polycrystalline Dy5Si2Ge2 as well. The magnetization vs field data at 1.8 K shows an ultra-sharp metamagnetic transition when field is applied along both the directions, in a critical field of about 28 kOe. It is observed that b axis is easy direction of magnetization. Magnetocaloric effect of this Dy5Si2Ge2 crystal has been estimated using magnetization vs field data obtained at various temperatures. A maximum magnetic entropy change (ΔSmmax) of ∼−15.6 J/kg/K has been observed at 22 K with field along b axis and ΔSmmax is ∼−11.2 J/kg/K at 54 K when field is parallel to ac plane, for a field change of 50 kOe. Occurrence of metamagnetic transition at temperatures below TN gives rise to a second peak at ∼22 K in the temperature dependent isothermal magnetic entropy change that leads to the observed large magnetocaloric effect.

The magnetic properties and the magnetic entropy change of La ( Fe 0.89 Si 0.11 ) 13 compounds under proton irradiation were investigated. With increasing proton fluence, the atomic displacement increased, which gave rise to increase of the lattice constant and Curie temperature. The magnetic entropy change slightly decreased with increasing proton fluence, but still remained large. Among the demonstrated attractive features of the materials, the maximum hysteresis loss almost disappeared and the relative cooling power increased slightly under proton irradiation.

Angle-resolved photoemission spectroscopy on a quasi-two-dimensional strongly correlated Ce 4f electron compound CeTe 2 has been performed to elucidate the importance of the three-dimensionality at the electronic structure in understanding its anomalous physical properties such as a complicated charge density wave formation. We have found that the Fermi surface as well as the band structure show the characteristic three-dimensionalities as follows: (1) a systematic reduction of the spectral weight at the hole-like Fermi surface along the Γ M line away from the ZR line suggests the imperfect nesting along the [ 1 1 0 ] axis; (2) the anomalous dispersive feature which is suggestive of the “band-folding” along the Γ Z line. The observed three-dimensionality indicates the existence of the three-dimensional nesting vector on CeTe 2 .

Specific heat of CeBi and CeSb, as well as LaBi and LaSb, was measured from 1.7 to 60 K under magnetic fields of up to 10 T. A Kondo like peak persists in CeBi in whole the studied region. In CeSb the effect of magnetic order is more significant but the similar situation exists, even though crossover from the Γ 7 dominated to Γ 8 dominated Kondo states appears. The γ-value is about 20 mJ/mol K 2 in both materials with weak field dependence. Phonon softening effect was also observed. It was shown that the extended ANNNI model including non-linear interactions can explain the essential feature of the complicated phase diagram in CeSb fairly satisfactorily.

We measured the electrical resistivity, magnetic susceptibility and specific heat of CeAs under several magnetic fields and showed that this compound has a Kondo behavior with an extremely low carrier concentration at high temperature.

GdSb and TmSb are typical ‘model’ materials in rare earth compounds. The former is an exchange interaction only sample and the latter is a CEF only sample. In order to compare the transport properties between the two samples, we have measured the Hall effect and resistivity of pure GdSb and TmSb in various fields. The CEF effect and magnetic scattering have been observed in both resistivity and Hall effect measurements for TmSb and GdSb, respectively. The mobilities of electrons and holes as well as the carrier concentration are calculated using the experimental data.

The magnetization process and Shubnikov-de Haas (SdH) effect have been investigated for CeAs single crystals in steady high magnetic fields up to 280 kOe using hybrid magnets. We found that a discontinuity appeared in the magnetization process and the magnetoresistivity had a hysteresis at the antiferro- (AFM) to ferromagnetic (FM) phase transition. An increase of the number of carriers and the structural change of Fermi surface were observed accompanied with the magnetic phase transition.

Reflectivity spectra of single crystals of CeIn 3 and CeTe show absorption due to the Kondo peak in the far infrared region at low temperature. The reflectivity spectra due to the conduction electron have been analyzed with the frequency dependence of the relaxation time of the conduction electron.

Single crystals of Ce 4 X 3 were prepared and measurements of magnetic and transport properties were done. Ce 4 Bi 3 exhibits the first-order magnetic phase transition and d H / d T of its boundary in the magnetic phase diagram is positive. Ce 4 X 3 indicate the crystal field effects in various properties except the reciprocal susceptibility of Ce 4 Bi 3 , which varies lineraly with the temperature.

We have measured the dHvA effect of CeSb down to 50 mK and discovered the largest hole Fermi surface, β 4 . The relative large electronic specific heat coefficient of CeSb compared with that of LaSb has been observed. These results are interpreted by the band calculation based on the p-f mixing model.

The frequency dependence of the dielectric constant and of the electrical conducitivity were measured by the Time Domain Spectroscopy (TDS). The temperature dependence of ϵ(ω) shows an anomaly at 305.5 K. From the analogy to the ferroelectric phase transition, our result suggests the occurrence of a charge ordered state associated with an electric dipole order.