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We report on detailed low-temperature measurements of the magnetization, the specific heat and the electrical resistivity on high-quality CeRuSn single crystals. The compound orders antiferromagnetically at T(N) = 2.8 K with the Ce(3+) ions locked within the a-c plane of the monoclinic structure. Magnetization shows that below T(N) CeRuSn undergoes a metamagnetic transition when applying a magnetic field of 1.5 and 0.8 T along the a- and c-axis, respectively. This transition manifests in a tremendous negative jump of ~25% in the magnetoresistance. The value of the saturated magnetization along the easy magnetization direction (c-axis) and the magnetic entropy above T(N) derived from specific heat data correspond to the scenario of only one third of the Ce ions in the compound being trivalent and carrying a stable Ce(3+) magnetic moment, whereas the other two thirds of the Ce ions are in a nonmagnetic tetravalent and/or mixed valence state. This is consistent with the low-temperature CeRuSn crystal structure i.e., a superstructure consisting of three unit cells of the CeCoAl type piled up along the c-axis, and in which the Ce(3+) ions are characterized by large distances from the Ru ligands while the Ce-Ru distances of the other Ce ions are much shorter causing a strong 4f-ligand hybridization and hence leading to tetravalent and/or mixed valence Ce ions.

Focuses on both the temperature and magnetic-field stability of the incommensurate antiferromagnetic phase in the complex magnetic phase diagram of UNiGe. Information on UNiGe; Specific heat of UNiGe; Description of the obtained magnetic phase diagram; Analysis of the magnetic phases in uranium intermetallics.

CsDy(MoO4)2 belongs to the family of binary alkaline rare-earth molybdates, with detectable low-temperature structural phase transitions, caused by the cooperative Jahn-Teller effect. Magnetocaloric studies of a single crystal of CsDy(MoO4)2 have been performed in the temperature range from 2 K to 18 K in magnetic fields up to 7 T applied along the crystallographic a axis. The maximum value of the isothermal entropy change is about 8 J/(kgK) and was achieved already in the fields above 2 T. The observed results suggest that the studied system can be used as a magnetic refrigerant at helium temperatures. [ABSTRACT FROM AUTHOR]

Two miniature uniaxial high-pressure CuBe cells have been designed for magnetic and neutron-diffraction studies of single crystals in a SQUID magnetometer and in a neutron diffractometer, respectively. Uniaxial elastic compression can be applied along or crosswise of the magnetic field direction or the diffractometer axis. Oriented single crystals are smoothly squeezed-up to a sample yield stress by a force of up to 20 kN produced by Bellville springs. The cell was successfully used for the study of huge anisotropy of magnetic interactions in the NdRhSn single crystal. [ABSTRACT FROM AUTHOR]

Abstract: We have studied interaction of components under different heat treatment conditions in a ternary Ce–Ru–Si system starting from the Ce20Ru60Si20 initial composition. The samples were characterized by powder X-ray diffraction and microprobe analysis. The formation of previously reported phases CeRu2Si2 and CeRu3Si2 was confirmed; two possibly novel phases (Ce35Ru58Si7; Ce3Ru2) were detected. A single-phase Ce35Ru58Si7 sample was prepared and its crystal structure was refined from powder diffraction data. Investigations of various physical properties of this material with respect to temperature and magnetic field revealed superconductivity below the critical temperature, T c =2.9K. The nature of the superconducting state is compared to the unconventional superconductivity coexisting with a static magnetic ordering in CeRu2. The formation of ternary phases from the Ce20Ru60Si20 composition is discussed in context of the phases in the Ce–Pt–Si system. [Copyright &y& Elsevier]

UCo2Si2 orders antiferromagnetically at TN=82.5 K. The magnetic ordering is accompanied by pronounced anomalies of the specific heat, magnetization and resistivity. Resistivity is notably anisotropic depending on the current direction. We have observed the evolution of the TN-related resistivity features with increasing hydrostatic pressure up to 7.3 GPa. TN value decreases with increasing pressure; the critical pressure for the collapse of the ordered magnetism is about 8 GPa. [ABSTRACT FROM AUTHOR]

We report on the results of a specific-heat study of a single crystal of UNi2Si2 in magnetic fields up to 14 T parallel to the c-axis. Analysis of the specific heat data reveals a magnetocaloric effect in UNi2Si2, that can be understood in terms of a competition of the applied magnetic field and strong antiferromagnetic correlations. [Copyright &y& Elsevier]

Abstract: A PrRhSn single crystal has been grown and investigated with respect to magnetic behavior. The magnetization and specific heat were measured as functions of temperature (range 2–300K) and magnetic field (range 0–9T) applied along the main crystallographic axes. A strong uniaxial magnetocrystalline anisotropy was observed with the -axis as the easy magnetization direction. The transition temperature from paramagnetic to ferromagnetic state was determined to be . The specific heat data exhibit a Schottky anomaly just above . The anomaly is lifted to higher temperatures with an applied magnetic field along the -axis yielding a considerable magnetocaloric effect. [Copyright &y& Elsevier]

Abstract: We have investigated a single crystal of NdFe2Si2 by variety of macro- and microscopic experiments in wide range of temperatures and magnetic fields. The results confirmed antiferromagnetic ordering below the Néel temperature T N≈14K and uniaxial magnetocrystalline anisotropy with easy magnetization direction along the c-axis. Specific heat and dilatometry data exhibit an additional sharp anomaly below the T N, in particular at T t=13.1K, which was tentatively considered as a signature of an order–order magnetic phase transition. The neutron diffraction experiment, however, reveals no evidence of an order–order magnetic phase transition and confirms existence of only one magnetic structure up to the T N with propagation vector . The temperature dependence of the electrical resistivity shows only a single anomaly (at T N), consistently with neutron diffraction results. Furthermore, comprehensive neutron diffraction experiment is scheduled. [Copyright &y& Elsevier]

Abstract: The temperature dependence of the specific heat of the itinerant 5f-electron antiferromagnet UIrGe was studied on a single crystal in magnetic fields up to 14T applied along the principal crystallographic directions. For fields along the c-axis, evolution of T N-related magnetic specific heat (magnetic entropy) anomaly is compared with the corresponding magnetization steps. [Copyright &y& Elsevier]

When a magnetic field is applied along the b-axis of the orthorhombic structure (TiNiSi-type) of CePtSn at temperatures below 3 K a sharp drop of resistance is observed when sweeping field up around 3 T. The original zero-field resistance is, however, not recovered when sweeping the field down through this critical field. Zero field neutron diffraction data reveal two propagation vectors q = (0, δ, 0) with δ1=0.469 and δ2=0.427 coexisting below 3 K. The field induced negative irreversible GMR effect around 3 T is found coinciding with suppression of the ‘δ2’ intensity in favor of the increasing ‘δ1’ one. A possible scenario for these phenomena will be discussed. [Copyright &y& Elsevier]

The thermal conductivity of CsGd(MoO4)2 has been studied in the temperature range from 2 to 50 K in zero magnetic field. The analysis of the data performed within the Debye model with the relaxation-time approximation revealed the presence of the scattering of phonons by critical fluctuations. The behaviour of phonon mean free path at the lowest temperatures is discussed. [ABSTRACT FROM AUTHOR]

In the presented work we report electrical, magnetic and thermal properties of EuB6- xCx single crystals with an estimated value of x ˜ 0.07. Our studies reveal an antiferromagnetic phase transition at TN ˜ 6.7 K. Electrical resistivity at zero magnetic field shows a pronounced resistivity maximum at TM ˜ 7 K, just above the antiferromagnetic phase transition temperature. With increasing applied magnetic field the maximum moves to lower temperature and becomes totally suppressed at the field of 9 T. Observed magnetoresistance is negative in the whole studied temperature range 2-20 K, yielding a ratio of ?(0 T, 7 K)/?(9 T, 7 K) ˜ 2.5. The origin of such magnetoresistance is associated with formation of mixed magnetic structure in the system due to fluctuation of carbon concentration. [ABSTRACT FROM AUTHOR]

Abstract: The magnetization (magnetic susceptibility), specific heat and electrical resistivity of a PrRhIn5 single crystal were studied. Van Vleck-type paramagnetic behavior and strong magnetocrystalline anisotropy were observed, which is attributed to a strong crystal-field effect on the Pr3+ ion. A crystal-field effect on the electrical resistivity was observed as well. We focused on the measurement of the specific heat down to low temperatures (down to 0.4K) in different magnetic fields. Indications of a field-induced transition to the quadrupolar ordered state below 0.4K were found in the specific-heat data in magnetic fields. First-principles calculations based on density functional theory of the electronic structure and crystal-field interaction were performed in order to better understand the experimental findings. [Copyright &y& Elsevier]

Abstract: The mean-field approach and crystal-field theory were employed in this work to study the magnetism of . We have derived several expressions for the magnetization induced by an external magnetic field and have determined the condition for occurrence of spontaneous magnetic ordering. Our theoretical analyses explain well why the system is paramagnetic in absence of a magnetic field and suggest that the system is always magnetically ordered if an external field is applied in the ab-plane, but remains paramagnetic for the magnetic field applied along c-direction. [Copyright &y& Elsevier]

A single crystal of the UCoAl0.75Sn0.25 quasiternary compound has been grown and studied by measuring the magnetization, specific heat and electrical resistivity at various temperatures and magnetic fields. Similar to the parent compounds UCoAl and UCoSn, the magnetization of their solid solution exhibits uniaxial anisotropy with a strong magnetic response along the c-axis and a weak and nearly temperature independent paramagnetic signal in the basal plane. The evolution of the c-axis magnetization isotherms, as well as the anomalies in the temperature dependence of the specific heat and resistivity point to ferromagnetism in UCoAl0.75Sn0.25 below TC≈5.5 K. The low value of the spontaneous magnetic moment, poor saturation of the magnetization, the pronounced negative magnetoresistance with increasing magnetic field and the temperature and magnetic field dependence of specific heat provide indications of strong fluctuations of the U magnetic moment also in the ferromagnetic state. [Copyright &y& Elsevier]

CsDy(MoO4)2 belongs to the family of binary alkaline rare-earth molybdates, with detectable low-temperature structural phase transitions, caused by the cooperative Jahn-Teller effect. Magnetocaloric studies of a single crystal of CsDy(MoO4)2 have been performed in the temperature range from 2 K to 18 K in magnetic fields up to 7 T applied along the crystallographic a axis. The maximum value of the isothermal entropy change is about 8 J/(kgK) and was achieved already in the fields above 2 T. The observed results suggest that the studied system can be used as a magnetic refrigerant at helium temperatures. [ABSTRACT FROM AUTHOR]

Magnetism in α-NdIr2Si2 single crystals has been probed through specific-heat, magnetization, magnetic susceptibility, and electrical resistivity measurements as a function of temperature, under an applied magnetic field, and for the magnetization curves under high hydrostatic pressures. Neutron diffraction experiments performed with powder and single-crystal samples were focused on microscopic aspects. Two collinear (Nd moments along the c axis) antiferromagnetic phases are found at low temperatures: a longitudinal sine-modulated structure with the magnetic propagation vector k = (0 0 5/6) at temperatures 18.2(2) K

NdRhSn has a ferromagnetic ground state [Tt=7.6(1) K] with a magnetic moment equal to 2/3 of the free Nd3+-ion moment. Upon cooling from the paramagnetic state, the ferromagnetism is preceded by an incommensurate antiferromagnetic state between TN=9.8(1) K and Tt. In both magnetic phases the magnetic moments are locked along the c axis, which is the easy-magnetization axis of the system. We have investigated this unusual situation by measuring anomalies of several bulk physical properties characteristic for the magnetic phase transitions at TN and Tt and the response of these properties to an applied magnetic field. Neutron-diffraction experiments have been also performed at low temperatures. Furthermore, in order to understand better the physical properties of NdRhSn, single crystals have been studied under external hydrostatic and uniaxial pressure and in high magnetic fields. An antiferromagnetic phase with a propagation vector (0 0 1/11) has been found between TN and Tt. The magnetic-ordering temperatures TN and Tt are sensitive to both hydrostatic and uniaxial pressures, but in a different manner. Application of hydrostatic pressure leads to a reduction of the ordering temperatures at rates ΔTN/Δp=-0.76(5) K/GPa and ΔTt/Δp=-0.9(2) K/GPa while uniaxial pressure applied along the c axis leads to an increase of the ordering temperatures at rates ΔTN/Δp=+1.2(5) K/GPa and ΔTt/Δp=+2.7(4) K/GPa. No considerable influence of pressure on the antiferromagnetic propagation vector has been found. The peculiar evolution of magnetism in NdRhSn with temperature indicates a complex hierarchy of exchange interactions. [ABSTRACT FROM AUTHOR]

Abstract: Specific heat of a single crystalline URhSi was measured by a relaxation method in a temperature range 0.3–25K in magnetic fields up to 8T applied along the two of the principal axes. The low-temperature specific heat exponentially decays with magnetic field. The decay is much faster in fields applied along the easy magnetization direction (the c-axis) than for the hard axis (the a-axis) case. A strong upturn in c p /T versus T below 0.6K that disappears with application of magnetic field is observed suggesting possible magnetic or superconducting phase transition at lower temperatures. The electrical resistivity in the vicinity of the ferromagnetic phase temperature is found to be reduced by more than 50% upon application of magnetic field of 8T applied along the c-axis. URhSi represent an itinerant ferromagnetic system with influence of spin fluctuations. [Copyright &y& Elsevier]

Abstract: Results of magnetization (M), AC-susceptibility , specific heat (C) and electrical-resistivity measurements on DyFe2Si2 single crystals are reported and analyzed in conjunction with first-principles electronic-structure calculations. Clear anomalies in the , and dependences indicate a magnetic-phase transition (paramagnetic ↔ antiferromagnetic) at 3.8K. Magnetic and specific-heat data obtained in magnetic fields (B) manifest uniaxial magnetocrystalline anisotropy with the easy magnetization direction along the c-axis of the tetragonal structure. These findings together with the metamagnetic transition observed on the curve measured at 2K and the evolution of the specific-heat anomaly at 3.8K in a magnetic field applied along the c-axis corroborate a scenario for the physics of DyFe2Si2 in terms of antiferromagnetism with Néel temperature . The first-principles electronic-structure calculations confirm the absence of an ordered Fe moment, which is in agreement with previously reported experimental findings. The magnetization isotherms and the temperature dependences of the specific heat and paramagnetic susceptibility in the paramagnetic state were analyzed taking into account the crystal-field interaction. The experimentally determined crystal-field parameters are compared with the results of first-principles crystal-field calculations. [Copyright &y& Elsevier]

Abstract: Results of specific heat and thermal conductivity measurements performed on the ErCo2 and Er(Co0.95Si0.05)2 compounds are presented with the emphasis on the phenomena associated with the magnetic ordering transition and their evolution with varying the chemical composition and the applied magnetic field. From specific heat data the magnetocaloric effect (MCE) in a wide temperature interval around the transition has been evaluated for several values of magnetic field. The maximum determined size of MCE makes these materials potentially applicable in magnetic cooling. The sensitivity of the Curie temperature (T C) to the Si substitution for Co without any dramatic suppression of MCE offers an effective way for tuning the temperature range available for magnetocaloric applications. The pronounced sharp thermal-conductivity anomaly in ErCo2 in the vicinity of T C is nearly suppressed in Er(Co0.95Si0.05)2. The role of spin fluctuations in these phenomena is discussed. [Copyright &y& Elsevier]

Abstract: Specific heat (SH) measurements on TbMn2(H,D)2 powders have been performed in the temperature range from 2 to 350K, in zero magnetic field and in 9T. Due to the low heat conductivity of the samples, the measurements were carried out on a mixed Cu- and sample-powder pellet. For TbMn2, the anti-ferromagnetic phase transition was manifest by a single SH peak at TN=47K, whereas a double SH peak at 281 and 288K and an upturn below 5K were observed for the hydride sample. Upon applying the magnetic field of 9T, the SH upturn was suppressed, whereas no visible influence was found on the specific heat in the whole temperature range above 10K as well as on the double peak. [Copyright &y& Elsevier]

The series of Er(Co1-yXy)2 compounds (X = p-electron element) with y≤0.05 was investigated regarding to magnetic, elastic, transport, and thermodynamic properties. A significant increase of Curie temperature (from 31 up to 52 K) caused by substitutions of p-electron elements for Co in ErCo2 (TC=31 K) and simultaneous weakening of the magnetoresistance and magnetocaloric effect accompanying the magnetic ordering transition have been observed. The related magnetovolume anomaly, on the other hand, is considerably reduced only when ErCo2 is doped by In. A change of the character of magnetic phase transition at TC has been observed in the case of Ge and In doping. [Copyright &y& Elsevier]

UCoAl has a paramagnetic ground state. Nevertheless, it exhibits a susceptibility maximum at Tmax≈20 K and a metamagnetic transition at lower temperatures that is induced by a magnetic field applied along the c-axis of the hexagonal ZrNiAl-type of structure. We have performed the first-principles electronic-structure calculations for this material in the framework of the density functional theory (DFT) and confirmed the close proximity of the threshold between the paramagnetic and the ferromagnetic state. Some aspects of the calculated charge-density distribution (e.g. the equilibrium volume and the electric-field gradient) are in good agreement with experiment but in contrast to earlier DFT studies it was found that the stable DFT ground state is ferromagnetic. The specific magnetic behavior is easily modified to ferromagnetism or conventional paramagnetism by doping UCoAl with suitable elements. To demonstrate these features we measured the magnetization as a function of magnetic field and temperature on single crystals of UCo1−xTxAl (T=Fe,Ni) solid solutions. In the course of this study, we investigated also the compounds UCo0.90Fe0.05Ni0.05Al and UFe0.50Ni0.50Al that are isoelectronic with UCoAl. All the studied compounds are isostructural with UCoAl and exhibit a strong uniaxial anisotropy with the dominating magnetic response along the c-axis. Ni substitution for Co leads to an increase of the critical field and to a gradual suppression of the metamagnetic transition, which disappears at x=0.10. On the other hand, Fe doping yields ferromagnetism. The compounds UCo0.90Fe0.05Ni0.05Al and UFe0.50Ni0.50Al also order ferromagnetically, below 30 and 52 K, respectively. [Copyright &y& Elsevier]

Abstract: We report on the evolution of magnetic phase transitions (MPTs) in the compounds investigated by means of electrical-resistivity and specific-heat measurements with respect to temperature and magnetic field. These materials apparently order antiferromagnetically and undergo two order–order transitions at lower temperatures, which was revealed by appearance and magnetic-field induced evolution of corresponding anomalies in the and curves. The Néel temperature, , decreases with increasing x. An applied magnetic field yields reduction of critical temperatures, suppression and smearing of the reported MPTs. [Copyright &y& Elsevier]

Abstract: Two series of RE(Co1− xXx )2 compounds (RE=Ho and Er, X=p-element) with were investigated regarding to magnetic, transport, elastic and thermodynamic properties. A significant increase of Curie temperatures caused by substitution of p-electron elements for Co has been observed. Simultaneously, weakening of the magnetoresistance and magnetocaloric effect together with suppression of the step on the thermal conductivity curve in the vicinity of the magnetic ordering transition was detected. A change of the character of the magnetic phase transition at has been observed in case of 3% Ge and In doping and for more than 7.5% doping of Si for RE=Er, respectively. [Copyright &y& Elsevier]

Abstract: Magnetization, susceptibility and resistivity were measured on the (antiferromagnetic with ) single crystal along both principal crystallographic axes in the temperature range 2–300K and in magnetic fields up to 14T. Magnetic properties were found to be isotropic. The susceptibility obeys the Curie–Weiss law with the effective magnetic moment A saturated moment of was determined at 2K. On the other hand, resistivity and magnetoresistivity are anisotropic and show an anomaly at . The anomalies in the susceptibility and resistivity data at are associated with the magnetic phase transition. [Copyright &y& Elsevier]

Results of low-temperature specific-heat (Cp) measurements of UNiAl single crystal in magnetic fields B&les;14 T are presented. At temperatures <7 K, this antiferromagnet exhibits a first-order metamagnetic transition at the critical field Bc&ap;11.4 T (when applied parallel to the c-axis). In the same temperature range, different Cp vs. T curves are obtained in zero magnetic field depending on the magnetic history of the sample (zero-field-cooled (ZFC)=cooling to T<7 K in zero field, field cooled (FC)=cooling in a field of 14 T parallel to c). The magnetic-field-induced irreversibility is clearly evidenced on the Cp/T vs. B data obtained at 3.2 K. For a measurement cycle; 0 (starting from ZFC state)→14→0 T the “increasing field” Cp, ZFC/T and “decreasing field” Cp, FC/T data clearly differ in fields <9 T and (Cp, ZFC/T)0 T>(Cp, FC/T)0 T. However in both cases, we have observed (for B<9 T) a Cp/T∼κcB2 dependence with different κc values. The results are discussed in the context of earlier-reported magnetic-history effects in magnetic and other electronic properties. [Copyright &y& Elsevier]

Magnetocaloric effect in the Haldane-gap S = 1 spin-chain [Ni(C2H8N2)2 NO2] (BF4) was investigated at low temperatures (kBT « J) and magnetic fields up to nominally 0.1 B sat, where J and B sat denote an exchange interaction and saturation magnetic field, respectively. Magnetic entropy was found to scale as exp (Δ/kBT) in zero magnetic field and T0.67 for B = Bc, in which the Haldane gap should be closed, in reasonable agreement with the theoretical predictions. The existence of the inverse magnetocaloric effect for B < Bc was confirmed. The occurrence of normal magnetocaloric response at lowest temperatures and magnetic fields was attributed to S = 1/2 degrees of freedom arising from the ends of chain segments. [ABSTRACT FROM AUTHOR]

In the presented work we report electrical, magnetic and thermal properties of EuB6- xCx single crystals with an estimated value of x ˜ 0.07. Our studies reveal an antiferromagnetic phase transition at TN ˜ 6.7 K. Electrical resistivity at zero magnetic field shows a pronounced resistivity maximum at TM ˜ 7 K, just above the antiferromagnetic phase transition temperature. With increasing applied magnetic field the maximum moves to lower temperature and becomes totally suppressed at the field of 9 T. Observed magnetoresistance is negative in the whole studied temperature range 2-20 K, yielding a ratio of ?(0 T, 7 K)/?(9 T, 7 K) ˜ 2.5. The origin of such magnetoresistance is associated with formation of mixed magnetic structure in the system due to fluctuation of carbon concentration. [ABSTRACT FROM AUTHOR]

Abstract: We have grown a CeCoGe single crystal and studied the specific heat as a function of temperature and magnetic field. At low temperatures also AC susceptibility and magnetization isotherms were measured. Clear attributes of the antiferromagnetic ordering below have been observed. The low-temperature specific heat (and the magnetic entropy) were considered when formulating a scenario of magnetic ordering in CeCoGe. [Copyright &y& Elsevier]

Abstract: We have prepared a polycrystalline sample of and studied the crystal structure and magnetic behavior. The tetragonal -type structure [M.V. Bulanova, et al., J. Alloys Compd. 345 (2002) 110] has been confirmed by powder X-ray diffraction. The magnetization and specific heat as functions of temperature and magnetic field show clear attributes of antiferromagnetic ordering below . The magnetization curve at 2K exhibits a metamagnetic transition around 0.7T. The high-temperature susceptibility obeys the Curie–Weiss law with the effective magnetic moment per Ce close to the free ion value. [Copyright &y& Elsevier]

Abstract: has been synthesized and studied by powder X-ray diffraction (at RT), specific heat, resistivity and magnetization measurements at temperatures from RT down to 0.4K and in magnetic fields up to 10T. A possible scenario for the ground state of based on the observed phenomena is proposed. [Copyright &y& Elsevier]