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We have measured the transverse elastic constants C 44 and C 66 of iron-based superconductor SrFe2(As1−xPx)2 (Sr122) single crystals as a function of temperature. Under-doped samples show elastic anomalies towards the structural/magnetic transition temperature. Optimal sample shows an upturn at the superconducting transition temperature in both C 44 and C 66 . These behavior is similar to Ba122, while only C 66 shows anomaly for Ba122. The elastic anomalies were analyzed by Jahn-Teller formula, and it was found that the Jahn-Teller energy of C 44 is much larger than that of C 66 . This indicates that monoclinic structural fluctuations exist inherently in Sr122 in addition to the known tetragonal fluctuations. Co-existence of these diverse fluctuations and their cooperation are a key to investigate the mechanism and properties of superconductivity in iron based superconductors.

Effect of pressure on the Curie temperature T C of the Mn-rich Heusler alloys Mn 2 RuSn and Mn 2 PdSn has been investigated by measuring the temperature dependence of initial permeability at various pressures up to 10 kbar. It was found that the Curie temperatures of Mn 2 RuSn and Mn 2 PdSn decrease with increasing pressure. The pressure derivatives of T C were estimated to be −0.59 K/kbar for Mn 2 RuSn and −0.80 K/kbar for Mn 2 PdSn. On the basis of the experimental results, the relationship between the magnetic transition temperature and the Mn-Mn distance is discussed.

With a view to understand the elastic behaviour of a material system, La 0.67 Sr 0.33− x Ba x MnO 3 (where x =0, 0.1, 0.2, and 0.33) especially in the vicinity of their magnetic transition temperature T C , a systematic investigation of ultrasonic velocity over a temperature range 300–400 K has been carried out. The materials prepared by citrate gel route, were characterized structurally by XRD and on analyzing the XRD patterns, it has been concluded that all the samples are having rhombohedral structure with space group of R3c. The magnetic ( T C ) transition temperatures determined by AC susceptibility measurements are found to decrease continuously with increasing barium concentration. Finally, the ultrasonic longitudinal velocities of all the samples are found to exhibit considerable softening in the vicinity of their magnetic transition temperatures, T C and the observed behaviour is explained using mean field theory and Jahn–Teller theorem.

The intermetallic magnetic compound YbCrSb 3 , which shows anomalous behavior when compared to other compounds in the RECrSb 3 series, is studied near zero magnetic field using μ SR . Coherent muon spin precession is observed, unambiguously establishing at the local level that a significant fraction of the sample is in a well-ordered magnetic state below ≈ 240 K . These results confirm, at the local level, that the magnetic transition temperature in YbCrSb 3 is higher than those of the other RECrSb 3 compounds synthesized to date.

Nanoparticles of the La 2/3 Sr 1/3 MiO 3 manganite were synthesized using the Pechini process and their structural properties were characterized by X-ray diffraction (XRD) and by transmission electron microscopy (TEM). The magnetization of compacted powders was measured for temperatures in the range 190≤ T≤450K. The estimated average diameter (D) of the particles continuously increased from 20 to 95 nm when the calcination temperature was varied from 873 to 1273 K. From the magnetic data we found that the room temperature saturation magnetization scaled with 1/D while the magnetic transition temperature follows a D 2 power-law suggesting that the correlation length ξ is mainly determined by the surface properties of the nanoparticles.

In this paper we report the results of low-temperature (from 1.7 to 40 K) heat-capacity studies in RPd2Al3 (R  Ce, Pr, Nd and Sm). Our heat-capacity data on CePd2Al3 and SmPd2Al3 agree with those of the previous studies. A λ-type anomaly is observed at 6.0 K for NdPd2Al3. A large jump (11 J/mol K) in heat-capacity data near the magnetic transition temperature confirms the bulk magnetic ordering in NdPd2Al3. The data for PrPd2Al3 do not show any magnetic ordering down to 1.7 K. We have calculated the magnetic contribution of entropy due to 4f electrons of all the samples. The temperature dependence of entropy in PrPd2Al3 indicates a nonmagnetic singlet ground state. The magnetic contribution to the entropy for all samples at 40 K is less than the corresponding free ion entropy values (R ln(2J + 1)). This suggests that there is a large crystal-field contribution to the heat-capacity in this series.

For double perovskite oxides Ba 2 FeMoO 6 (BFMO) and Sr 2 FeMoO 6 (SFMO), resistivity and magnetization have been measured under pressure and magnetic field. By applying pressure the magnetic transition temperature T C is largely and slightly enhanced for BFMO and SFMO, respectively. The different value of T C between BFMO and SFMO can be explained in terms of the chemical pressure effect. The saturation magnetization does not exhibit the pressure dependence in both of BFMO and SFMO. The resistivity of BFMO is drastically reduced by applying pressure, although the pressure effect on magnetoresistance is quite small, indicating that the components of conduction which contribute to the colossal magnetoresistance effect hardly depends on pressure.

We have studied the effect of pressure on the magnetic transition in CeRh 2 Ge 2 and CeRu 2 Ge 2 by electrical resistance measurements in the temperature range between 1.2 K and 300 K. Both samples show two magnetic transitions below 30 K. In CeRh 2 Ge 2 , the magnetic transition temperatures increase with increasing pressure. In the case of CeRu 2 Ge 2 , the upper magnetic transition temperature increases with pressure, whereas the lower one decreases with increasing pressure

Magnetic properties of CeP at high pressure have been investigated by the measurement of magnetization up to 1.6 GPa. The present result shows the gradual increase of the paramagnetic susceptibility, χ ( T ) and the steep raise of the magnetic transition temperature with increasing pressure. The pressure dependence of χ ( T ) indicates that the contribution of the crystal field at low temperatures was strongly affected by applied pressure. The behaviour of χ ( T , P ) has been analysed by using the crystal field splitting energy and the exchange interactions as the fitting parameters.

We have performed an ultrasonic measurement to investigate the elastic properties of the skutterudite compound NdFe 4 P 12 . A softening has been observed in all measured elastic constants, C 11 , (C 11 - C 12 )/2 and C 44 around the magnetic transition temperature T c of 1.9 K. The elastic softening is explained well on the basis of the crystalline electric field (CEF) effect. The theoretical fitting of the obtained results suggests that Γ (2) 67 quartet of Nd 3+ ion is plausible as the CEF ground state in NdFe 4 P 12 .

By the chemical, magnetic and X-ray-analysis, the production of Ni(OH)2-monolayer-microclusters was identified in the precipitates from the mixing of aqueous solutions of NiCl2·6H2O and Na2SiO3·nH2O (n=0 or 9). The magnetic transition temperature of 10.2K was discussed, based on the finite size effect in the magnetic microcluster.