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The multicaloric effect is described by a temperature or entropy change of a material triggered by external stimuli applied or removed simultaneously or sequentially. The prerequisite for this is a material exhibiting multiple ferroic states. However, direct measurements of the effect are rarely reported. Now, for this reason, we built a measurement device allowing to determine the adiabatic temperature change in pulsed magnetic fields and, simultaneously, under the influence of a uniaxial load. We selected the all- d -metal Heusler alloy Ni–Mn–Ti–Co for our first test because of its enhanced mechanical properties and enormous magneto- and elastocaloric effects. Ni–Mn–Ti–Co was exposed to pulsed magnetic fields up to 10 T and uniaxial stresses up to 80 MPa, and the corresponding adiabatic temperature changes were measured. With our new experimental tool, we are able to better understand multicaloric materials and determine their cross-coupling responses to different stimuli. [ABSTRACT FROM AUTHOR]

The performance of iron-based superconductors in high magnetic fields plays an important role for their practical application. In this work, we measured the magnetostriction and magnetization of BaFe1.908Ni0.092As2 single crystals using pulsed magnetic fields up to 60 T and static magnetic fields up to 33 T, respectively. A huge longitudinal magnetostriction (of the order of 10–4) was observed in the direction of twin boundaries. The magnetization measurements evidence a high critical-current density due to strong bulk pinning. By using magnetization data with an exponential flux-pinning model, we can reproduce the magnetostriction curves qualitatively. This result shows that the magnetostriction of BaFe1.908Ni0.092As2 can be well explained by a flux-pinning-induced mechanism. [ABSTRACT FROM AUTHOR]

We present an overview of selected copper-based quasi-2D square-lattice spin-1/2 materials with an easy-plane anisotropy, providing the possibility to study emergent Berezinskii-Kosterlitz-Thouless (BKT) correlations. In particular, in those materials with a comparatively small exchange coupling, the effective XY anisotropy of the low-temperature spin correlations can be controlled by an applied magnetic field, yielding a systematic evolution of the BKT correlations. In cases where the residual interlayer correlations are small enough, dynamical BKT correlations in the critical regime may be observed experimentally, whereas the completion of the genuine BKT transition is preempted by the onset of long-range order. [ABSTRACT FROM AUTHOR]

Magnetic fields are key ingredients for heating the solar corona to temperatures of several million Kelvin. A particularly important region with respect to this is the so-called magnetic canopy below the corona, where sound and Alfvén waves have roughly the same speed and can, therefore, easily transform into each other. We present the results of an Alfvén-wave experiment with liquid rubidium carried out in a pulsed field of up to 63T. At the critical point of 54T, where the speeds of Alfvén waves and sound coincide, a new 4 kHz signal appears in addition to the externally excited 8 kHz torsional wave. This emergence of an Alfvén wave with a doubled period is in agreement with the theoretical predictions of a parametric resonance between the two wave types. We also present preliminary results from numerical simulations of Alfvén and magneto-sonic waves using a compressible MHD code. [ABSTRACT FROM AUTHOR]

We study the dependence of the magnetocaloric effect on the magnetic field-change-rate the first order magnetostructural transition in Mn3GaC by measuring the adiabatic temperature change ΔT at three different time scales: 11mTs-1, 700mTs-1, and ~1000T s-1. We find that the maximum adiabatic temperature-change of about 5K is reached in the 11mTs-1 and 700mTs-1 rates, whereas for the ~1000 T s-1-rate the transition lags the change in the magnetic field so that the maximum adiabatic temperature-change is not attained. [ABSTRACT FROM AUTHOR]

The present pulsed high-magnetic-field study on Ni50Mn35In15 gives an extra insight into the thermodynamics of the martensitic transformation in Heusler shape-memory alloys. The transformation-entropy change, ΔS, was estimated from field-dependent magnetization experiments in pulsed high magnetic fields and by heat-capacity measurements in static fields. We found a decrease of ΔS with decreasing temperature. This behavior can be understood by considering the different signs of the lattice and magnetic contributions to the total entropy. Our results further imply that the magnetocaloric effect will decrease with decreasing temperature and, furthermore, the martensitic transition is not induced anymore by changing the temperature in high magnetic fields. [ABSTRACT FROM AUTHOR]

We present the first study of codoped iron-arsenide superconductors of the 122 family (Sr/Ba)1-x Kx Fe2-y Coy As2 with the purpose to increase the upper critical field Hc2 compared to single doped Sr/BaFe2 As2 materials. Hc2 was investigated by measuring the magnetoresistance in high pulsed magnetic fields up to 64 T. We find, that Hc2 extrapolated to T=0 is indeed enhanced significantly to ≈ 90 T for polycrystalline samples of Ba0.55 K0.45 Fe1.95 Co0.05 As2 compared to ≈75 T for Ba0.55 K0.45 Fe2 As2 and BaFe1.8 Co0.2 As2 single crystals. Codoping thus is a promising way for the systematic optimization of iron-arsenic based superconductors for magnetic-field and high-current applications. [ABSTRACT FROM AUTHOR]

Viscosity measurements in combination with pulsed magnetic fields are developed by use of a quartz-crystal microbalance (QCM). When the QCM is immersed in liquid, the resonant frequency, f0, and the quality factor, Q, of the QCM change depending on (ρη)0.5, where ρ is the mass density and η the viscosity. During the magnetic-field pulse, f0 and Q of the QCM are simultaneously measured by a ringdown technique. The typical resolution of (ρη)0.5 is 0.5%. As a benchmark, the viscosity of liquid oxygen is measured up to 55 T. [ABSTRACT FROM AUTHOR]

We report results of magnetic and ultrasound studies of the sulfide spinel CoCr2S4, for which the multiferroicity has recently been suggested. Clear anomalies in the magnetic and acoustic properties have been observed at TN = 222K and in applied magnetic fields evidencing the important role of magnetoelastic interactions in this material. In contrast, no anomalies have been detected at TC = 28 K, where a spontaneous electric polarization and isostructural distortions have been reported. We have extracted the H-T phase diagram of CoCr2S4 from our experiments for magnetic fields applied along the h111i direction. We discuss our observations in relation to our earlier results obtained for the oxide multiferroic spinel CoCr2O4. [ABSTRACT FROM AUTHOR]

We have studied the magnetocaloric effect (MCE) in the shape-memory Heusler alloy Ni50Mn35In15 by direct measurements in pulsed magnetic fields up to 6 and 20 T. The results in 6 T are compared with data obtained from heat-capacity experiments. We find a saturation of the inverse MCE, related to the first-order martensitic transition, with a maximum adiabatic temperature change of δTad=-7K at 250K and a conventional field-dependent MCE near the second-order ferromagnetic transition in the austenitic phase. The pulsed magnetic field data allow for an analysis of the temperature response of the sample to the magnetic field on a time scale of ~10 to 100ms, which is on the order of typical operation frequencies (10-100 Hz) of magnetocaloric cooling devices. Our results disclose that in shape-memory alloys, the different contributions to the MCE and hysteresis effects around the martensitic transition have to be carefully considered for future cooling applications. [ABSTRACT FROM AUTHOR]

We have studied the magnetocaloric effect (MCE) in the shape-memory Heusler alloy Ni50Mn35In15 by direct measurements in pulsed magnetic fields up to 6 and 20 T. The results in 6 T are compared with data obtained from heat-capacity experiments. We find a saturation of the inverse MCE, related to the first-order martensitic transition, with a maximum adiabatic temperature change of △Tad = --7 K at 250 K and a conventional field-dependent MCE near the second-order ferromagnetic transition in the austenitic phase. The pulsed magnetic field data allow for an analysis of the temperature response of the sample to the magnetic field on a time scale of ~10 to 100 ms, which is on the order of typical operation frequencies (10-100 Hz) of magnetocaloric cooling devices. Our results disclose that in shape-memory alloys, the different contributions to the MCE and hysteresis effects around the martensitic transition have to be carefully considered for future cooling applications. [ABSTRACT FROM AUTHOR]

Results of systematic high-frequency electron spin resonance (ESR) studies of BaCrO, a weakly coupled $S=\frac{1}{2}$ dimer system, in magnetic fields up to 25 T are reported. Two pairs of ESR gapped modes corresponding to transitions from a spin-singlet ground state to the first excited triplet states with gaps, Δ=563 GHz and Δ=399 GHz, are revealed below H=12.5 T. The detection of the ground-state excitations by means of ESR clearly indicates the presence of a non-secular term allowing these transitions. A complex structure of the microwave absorption spectrum in magnetic fields above H is observed, those peculiarities are discussed. [ABSTRACT FROM AUTHOR]

Results of electron spin resonance studies of copper pyrimidine dinitrate (Cu-PM, [PM-Cu(NO)(HO)], PM = pyrimidine), a spin-1/2 antiferromagnetic chain material with alternating g-tensor and Dzyaloshinskii-Moriya interactions, in pulsed magnetic fields up to 63 T are reported. The field-induced gap shows a non-monotonic behavior with a minimum in the vicinity of the saturation field H=48.5 T. This is associated with a transition from the sine-Gordon region to a spin-polarized state with magnon excitations. By comparing the entire set of experimental data with results of density matrix renormalization group calculations for Cu-PM, the validity of the used theoretical approach is proven. [ABSTRACT FROM AUTHOR]

In this short review, we report on the recently found growing experimental evidence for the existence of Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) states in quasi-two-dimensional organic superconductors. At high magnetic fields aligned parallel to the conducting organic layers, we observe an upturn of the upper critical field beyond the Pauli limit, as evidenced by specific-heat and torque-magnetization measurements. Inside the superconducting state a second thermodynamic transition emerges. These features appear only in a very narrow angular region close to parallel-field orientation. [ABSTRACT FROM AUTHOR]

The Dresden High Magnetic Field Laboratory (HLD) is a user facility which provides scientists with the possibility to perform a broad range of experiments in pulsed magnetic fields. Recent progress in the magnet-technology development at the HLD has led to significant advances in achieving non-destructive pulsed magnetic fields close to the megagauss mark. Using 9.5 MJ dual-coil magnets with 16 mm bore, in 2011 a world-record field of 91.4 T has been achieved. Later 94.2 T have been reached. We report on the magnet design and performance of these magnets as well as on the design for the next generation of dual-coil magnets characterized by interchangeable inner sub-coils and improved control of the axial preload. [ABSTRACT FROM AUTHOR]

The magnetization of ErFeTi and HoFeTi single crystals was measured in pulsed magnetic fields up to 60 T. A number of field-induced phase transitions were observed. The inter-sublattice molecular fields were found to be 60 T in ErFeTi and 73 T in HoFeTi. [ABSTRACT FROM AUTHOR]

We present the temperature dependence of the specific heat of CoCrO between 2.08 K and 306 K in zero magnetic field. The lattice component can be described by the Komada-Westrum model with a characteristic temperature Θ = 541 K. The entropy of the magnetic component amounts to 33.51 J mol K at T = 298.15 K, in good agreement with the magnetic entropy of Co and Cr ions with completely quenched orbital moments. We compare our results with data available in literature. [ABSTRACT FROM AUTHOR]

We report on the design and successful testing (up to 55 T) of a 60 T long-pulse (LP) magnet with a pulse duration of 1500 ms at the Hochfeld-Magnetlabor Dresden. This magnet has the capability of producing magnetic fields with time and homogeneity characteristics suitable to host specific-heat and nuclear magnetic resonance (NMR) experiments. We describe the development of a specific-heat probe for this magnet, which uses the quasi-adiabatic heat-pulse method and enables magnetocaloric-effect measurements. Furthermore, we report the implementation of a NMR setup, consisting of home-built probe and spectrometer. Both experimental devices were tested successfully in the LP magnet up to 31 and 44 T, respectively. [ABSTRACT FROM AUTHOR]

We report on the use of the colossal magnetoresistance (CMR) effect in manganites for the measurement of pulsed magnetic fields up to the megagauss limit. To increase the application range in a magnetic field, we fabricated nanostructured La-Sr-Mn-O films consisting of nanocrystallites cummulated into clusters separated by highly amorphous inter-cluster boundaries. We demonstrate that the CMR effect does not saturate in these films at 77 K up to 91.4 T. Moreover, the magnetoresistance behavior at 290 K shows that nanostructured manganite films are promising candidates for the development of magnetic field scalar sensors operating in wide field and temperature ranges. [ABSTRACT FROM AUTHOR]

We report measurements of the temperature dependence of the radio frequency magnetic penetration depth in BaKFeAs and Ba(FeCo)As single crystals in pulsed magnetic fields up to 60 T. From our data, we construct an H- T-phase diagram for the inter-plane ( H | c) and in-plane ( H | ab) directions for both compounds. For both field orientations in BaKFeAs we find a concave curvature of the H( T) lines with decreasing anisotropy and saturation towards lower temperature. Taking into account Pauli spin paramagnetism we can describe H( T) and its anisotropy. In contrast, we find that Pauli paramagnetic pair breaking is not essential for Ba(FeCo)As. For this electron-doped compound, the data support a H( T) dependence that can be described by the Werthamer-Helfand-Hohenberg model for H | ab and a two-gap behavior for H | c. [ABSTRACT FROM AUTHOR]

Early work on the iron-arsenide compounds supported the view, that a reduced dimensionality might be a necessary prerequisite for high- T superconductivity. Later, however, it was found that the zero-temperature upper critical magnetic field, H(0), for the 122 iron pnictides is in fact rather isotropic. Here, we report measurements of the temperature dependence of the electrical resistivity, ρ( T), in BaKFeAs and BaKFeAs single crystals in zero magnetic field and in BaKFeAs in static and pulsed magnetic fields up to 60 T. We find that the resistivity of both compounds in zero field is well described by an exponential term due to inter-sheet umklapp electron-phonon scattering between light electrons around the M point to heavy hole sheets at the Γ point in reciprocal space. From our data, we construct an H- T phase diagram for the inter-plane ( H | c) and in-plane ( H | ab) directions for BaKFeAs. Contrary to published data for 122 underdoped FeAs compounds, we find that H( T) is in fact anisotropic in optimally doped samples down to low temperatures. The anisotropy parameter, γ = H/ H, is about 2.2 at T. For both field orientations we find a concave curvature of the H lines with decreasing anisotropy and saturation towards lower temperature. Taking into account Pauli spin paramagnetism, we perfectly can describe H and its anisotropy. [ABSTRACT FROM AUTHOR]

In this paper we present a portable quantum cascade laser (QCL) based infrared magnetospectrometer covering the spectral range from 5 to 120 μm. The variation of the excitation wavelength is enabled by an easy change of the QCL plug-in modules, while the use of any other external source is also possible. The performance of the setup is illustrated via cyclotron-resonance studies under pulsed magnetic fields up to 60 T. [ABSTRACT FROM AUTHOR]

In this paper we consider various issues of design, fabrication, and performance of non-destructive pulsed magnets at the Dresden High Magnetic Field Laboratory. Currently, a variety of pulsed magnets are in operation in the laboratory. A 70 T/8.5 MJ magnet, having a 24 mm bore and generating field pulses of about 150 ms duration serves as a workhorse for external users and for in-house research. Smaller 60-65 T/1.5 MJ magnets with a bore of 20 mm and pulse duration of ~25 ms have been proven to be very reliable in operation. In addition, a new 90 T/9 MJ dual-coil magnet has recently achieved 87.2 T in a 20 mm bore. A 60 T/43 MJ long-pulse magnet is currently tested. Questions of magnet longevity, coil monitoring, as well as magnetic-field measurements are addressed. Further magnet-technology developments and the route to 100 T are discussed. [ABSTRACT FROM AUTHOR]

The transverse acoustic wave propagating along the [100] axis of the cubic paramagnet Tb3Ga5O12 (TGG) exhibits amplitude oscillations as a function of magnetic field applied in the direction of propagation. This magneto-acoustic Faraday effect shows a linear frequency dependence contrary to theoretical expectation which demands a quadratic frequency dependence. The c44 mode demonstrates also a strong softening of 6% up to 19 T, the magnetic field where an energy level of the CEF triplet branch starts to cross the quasi-doublet branch. This softening has the same origin, the magneto-elastic coupling, as the anomalies in the temperature dependence of the elastic constants and the magneto-acoustic Faraday effect. [ABSTRACT FROM AUTHOR]

We report on pulsed-field magnetization studies of the quasi-two-dimensional spin system [Cu(pyz)2(HF2)]PF6. The magnetization saturates at $B_{C}^{ab}=37.5$ T and $B_{C}^{c}=33.8$ T for in-plane and out-of-plane orientations of the applied magnetic field, respectively. In addition, the angular dependence of the g-factor studied by electron-spin resonance reveals orbital overlap in the ab plane suggesting a quasi-two-dimensional square-lattice network of Cu spins. It is argued that the high-field behavior is governed by the two-dimensional nature of the spin correlations due to the large anisotropy of the exchange couplings. [ABSTRACT FROM AUTHOR]

We present a non-perturbative theory of paramagnetically-driven superconducting (SC) phase transitions in heavy-fermion metals, which reliably determines their stable SC phases, treats properly the corresponding finite jumps of the order parameter, and can account for unusual features reported recently for this type of materials. It is found that for quasi-2D heavy-fermion metals, such as CeCoIn5, at high magnetic fields oriented perpendicular to the highly conducting planes, the effect of the Fulde-Ferrel (FF) modulation is too weak to prevent a direct first-order phase transition from the normal to the uniform SC state. For 3D heavy-fermion metals, such as URu2Si2, the FF modulation stabilizes, under a decreasing magnetic field, a non-uniform SC state via a second-order phase transition from the normal state. However, at a slightly lower field the modulated phase becomes unstable, transforming to a uniform SC state via a first-order transition. [ABSTRACT FROM AUTHOR]

Microminiature Hall probes (MHP) may be used as magnetic field transducers, with virtually no change of sensitivity with temperature, for applications at room and cryogenic temperatures. The probes have a nominal active sensing area from 90×90 μm down to 20×20 μm and are based on Sn-doped n-InSb/i-GaAs MBE-grown heterostructures. MHPs were intensively tested in static (up to 14 T) and pulsed magnetic fields and shown to be appropriate for various applications in the temperature range 2–300 K and in pulsed magnetic fields up to 87 T. The latest version of these probes, with overall cross-section thickness-width dimensions of 150×750 μm, are the smallest encapsulated Hall probes currently available and can be placed in areas not previously accessible to commercial packaged or unpackaged sensors. [ABSTRACT FROM AUTHOR]

We report on results of sound-velocity and sound-attenuation measurements in the triangular-lattice spin-1/2 antiferromagnet Cs2CuCl4 ( T N=0.6 K), in external magnetic fields up to 14 T, applied along the b axis, and at temperatures down to 300 mK. The results are analyzed with a quasi-two-dimensional hard-core boson theory based on exchange-striction coupling. There is a good qualitative agreement between theoretical and experimental results. [ABSTRACT FROM AUTHOR]

We report on measurements of the magnetization up to 7 T, of the specific heat and electrical resistivity in fields up to 14 T, and of the magnetic susceptibility in fields up to 20 T of a polycrystalline sample of Rh17S15. Our data allow us to complement the superconducting phase diagram. The existence of narrow 4 d-band states (and thus of strong electronic correlations that seem not to provide magnetic correlations) is supported by the moderately high electronic contribution to the specific heat of about 107 mJ/molK2, favoring the existence of a strong superconducting interaction. This fact, and the remarkably high upper critical field (exceeding the simple Pauli limit by a factor of two), give evidence of the uncommon nature of the superconductivity in Rh17S15. [ABSTRACT FROM AUTHOR]

We report resistivity and upper critical field B c2( T) data for As-deficient LaO0.9F0.1FeAs1− δ in a wide temperature and field range up to 60 T. These disordered samples exhibit a slightly enhanced superconducting transition at T c=29 K and a significantly enlarged slope d B c2/d T=−5.4 T/K near T c which contrasts with a flattening of B c2( T) starting near 23 K above 30 T. This flattening is interpreted as Pauli limiting behavior (PLB) with B c2(0)≈63 T. We compare our results with B c2( T)-data reported in the literature for clean and disordered samples. Whereas clean samples show no PLB for fields below 60 to 70 T, the hitherto unexplained flattening of B c2( T) for applied fields H ∥ ab observed for several disordered closely related systems is interpreted also as a manifestation of PLB. Consequences of our results are discussed in terms of disorder effects within the frame of conventional and unconventional superconductivity. [ABSTRACT FROM AUTHOR]

We report on results of sound velocity and sound-attenuation measurements performed on the antiferromagnetic ( T N=48 K) UCuGe. The measurements have been done on a UCuGe single crystal at different frequencies for longitudinal ultrasound waves propagating along the [001] direction in static (up to 18 T) and pulsed (up to 60 T) magnetic fields applied along the same direction. The temperature dependences of the sound velocity and attenuation display a pronounced anomaly at T N, which is evidence for a strong magneto-elastic interaction. The pulse-field measurements at 4.2 K show a minimum in the sound velocity followed by a jump-like anomaly at 37 T, and another kink-like anomaly at 48–49 T. These anomalies are due to field-induced spin rearrangements as measured in magnetization studies. In the paramagnetic state ( T> T N), both acoustic characteristics show large frequency-dependent changes revealing the presence of an unusual relaxation mechanism which might be due to vacancy dynamics. [ABSTRACT FROM AUTHOR]

We report results on ultrasound studies of the frustrated magnet CdCr2O4. This compound demonstrates an antiferromagnetic ordering at T N=7.8 K and a metamagnetic phase transition at 28 T followed by a wide magnetization plateau with one half of the full moment of S=3/2 of Cr3+ ions. A longitudinal acoustic mode in the [111] crystallographic direction exhibits pronounced effects both in the temperature and magnetic-field dependencies. Pulsed-field measurements show a drastic change in the sound velocity just below and above the 1/2 magnetization plateau. Our results suggest a large spin-strain coupling and give evidence for a pronounced interplay between spin and lattice degrees of freedom in CdCr2O4. [ABSTRACT FROM AUTHOR]

The successful use of picosecond-pulse free-electron-laser (FEL) radiation for the continuous-wave terahertz-range electron spin resonance (ESR) spectroscopy has been demonstrated. The combination of two linac-based FELs (covering the wavelength range of 4–250 μm) with pulsed magnetic fields up to 70 T allows for multifrequency ESR spectroscopy in a frequency range of 1.2–75 THz with a spectral resolution better than 1%. The performance of the spectrometer is illustrated with ESR spectra obtained in the 2,2-diphenyl-1-picrylhydrazyl and the low-dimensional organic material (C6H9N2)CuCl3. [ABSTRACT FROM AUTHOR]

The design of a high-energy pulsed magnet is a challenging task and usually implies substantial calculation efforts. As the maximum stress is located in the midplane of the magnet, this region is usually the only focus of analysis. For that a number of well-established algorithms are available. However, the coil performance is governed not exclusively by the midplane. Therefore, it is important to simulate the whole coil behavior. Here we report on a simulation approach used among others at the Hochfeld-Magnetlabor Dresden (HLD). Assuming axial symmetry of the coil, the cross section of the magnet is modeled by finite elements. We illustrate this simulation technique for an 8.5 Mi 70 Tesla mono-coil and a 46 Mi double-coil magnet designed at the HLD. [ABSTRACT FROM AUTHOR]

Based on field-cooled dc-magnetization measurements in a SQUID magnetometer with carefully controlled magnetic-field profiles, we present evidence that diamagnetism is missing in the superconducting state (T < 50 K) of the (weakly) ferromagnetic (TM ≈130 K) superconductor RuSr2GdCu2O8 (Ru1212). Nevertheless, taking into account the granular nature of the samples investigated so far, this cannot be taken as evidence for the lack of a Meissner state or bulk superconductivity. It is shown that for low applied magnetic fields a vortex state most probably involves the intergrain area (area between the grains) rather than the individual grains (bulk Ru1212). Furthermore, the wide superconducting transition of Ru1212 (Tc,onset = Tc ≈48 K, Ts(R = 0) = Ts = 32 K) realized in resistance measurements in zero applied magnetic field can be readily understood as the effect of resistive grain contacts and is not necessarily related to the movement of spontaneously induced vortices in bulk Ru1212, as it has been suggested previously. A comparison of the low-temperature specific heat of Sr2GdRuO6 (Sr2116), the precursor for the preparation of Ru1212 and thus a possible impurity phase, with previously reported data for Ru1212 shows that it is unlikely that Sr2116 is responsible for the specific-heat features attributed to the superconductivity of Ru1212 and supports the existence of a bulk superconducting state in the latter compound. [ABSTRACT FROM AUTHOR]

Progress and recent achievements in coil design are presented for the new Dresden High Magnetic Field Laboratory (HLD), which is under construction at the Forschungszentrum Rossendorf. This laboratory is planned to be open for external users in 2007. The facility is placed near a free electron laser which will offer the opportunity to perform infrared spectroscopy in pulsed magnetic fields. Implementation of various experimental techniques, such as transport, magnetization, specific heat, ultrasound, and magnetic resonance in pulsed magnetic fields up to 100 T are planned. Typical pulse durations will be in the range between 10 and 1000 ms with magnet bores ranging from 20 to 40 mm. The pulsed magnets will be energized by a 50 M J/24 kV modular capacitive pulsed-power supply. With our newly designed coils, so far we were able to reach 65 T in a non-destructive manner. These coils are built using regular copper wire reinforced with an organic fiber (Zylon). Pulse durations for the various coils are between 20 and 50 ms. Different magnet failure modes have been analysed and possible improvements of the magnets are discussed. We also present numerical simulations of our pulsed magnets. [ABSTRACT FROM AUTHOR]

We present a theory which is able to explain enhanced magnetic quantum-oscillation amplitudes in the superconducting state of a layered organic metal with incoherent electronic transport across the layers. The incoherence acts through the deformation of the layer-stacking factor, which becomes complex and decreases the total scattering rate in the mixed state. This novel mechanism restores the coherence by establishing a long-range order across the layers and can compensate the usual decrease of the Dingle factor below the upper critical magnetic field caused by the intralayer scattering. [ABSTRACT FROM AUTHOR]

Electrical-transport measurements of the semimetal CeBiPt in magnetic fields up to 60 T reveal a drastic change of the electronic band structure. The oscillating Shubnikov–de Haas signal vanishes above about 25 T although the quantum limit is not yet reached. Above this field the magnetoresistance rises strongly independent of angle and temperature. These unique features are caused by the Ce 4f electrons as evidenced by the absence of any unconventional behavior in the sister compound LaBiPt. [Copyright &y& Elsevier]

The Dresden High Magnetic Field Laboratory (HLD) is a pulsed-field user facility which offers to researches a variety of experimental techniques combined with non-destructive pulsed magnetic fields. Recently a new, 9.5 MJ dual-coil magnet has been commissioned. This magnet has achieved magnetic field of 91.4 T in a 16 mm bore and it is available for users now. In this paper, we report on some key upgrades in the magnet design which have led to breaking the 90 T limit at the HLD. Further possible design improvements are discussed. In addition, we share our operational experience obtained with the pulsed magnets. [ABSTRACT FROM PUBLISHER]

Abstract: We report on resistance and Hall-effect measurements of the half-Heusler compound CeBiPt in pulsed magnetic fields up to 70T. The band structure of the semimetal CeBiPt depends highly sensitively on temperature, magnetic field, and stoichiometry. This is reflected by the observed sample-dependent threshold fields above which the Shubnikov–de Haas signal disappears and at which clear changes of the Hall coefficient occur. [Copyright &y& Elsevier]

Interacting electrons confined to their lowest Landau level in a high magnetic field can form a variety of correlated states, some of which manifest themselves in a Hall effect. Although such states have been predicted to occur in three-dimensional semimetals, a corresponding Hall response has not yet been experimentally observed. Here, we report the observation of an unconventional Hall response in the quantum limit of the bulk semimetal HfTe5, adjacent to the three-dimensional quantum Hall effect of a single electron band at low magnetic fields. The additional plateau-like feature in the Hall conductivity of the lowest Landau level is accompanied by a Shubnikov-de Haas minimum in the longitudinal electrical resistivity and its magnitude relates as 3/5 to the height of the last plateau of the three-dimensional quantum Hall effect. Our findings are consistent with strong electron-electron interactions, stabilizing an unconventional variant of the Hall effect in a three-dimensional material in the quantum limit. There is a long-standing experimental effort to observe field-induced correlated states in three-dimensional materials. Here, the authors observe an unconventional Hall response in the quantum limit of the bulk semimetal HfTe5 with a plateau-like feature in the Hall conductivity. [ABSTRACT FROM AUTHOR]

Pulsed magnetic fields up to 68 Tesla have been used to determine the intersublattice coupling strength and its temperature dependence of GdCo12B6 compound. This compound exhibits ferrimagnetic behaviour below 163 ± 2 K. Two antiferromagnetically coupled sublattices cancel out at compensation temperature at about 48 K. They are carrying magnetization of typically 0.42 μB/Co atom and 7 μB/Gd. The intrinsic magnetic properties of the GdCo12B6 compound have been determined by combining low temperature magnetic measurements in both steady and pulsed magnetic field, as well as isofield studies in steady field. At 4.2 K, the magnetization curve of GdCo12B6 is found to reach the full saturation with sum of both sublattice magnetizations for an applied magnetic field of about 68 T. In addition a detailed study is presented in the whole ordered temperature range on the basis of magnetization curves recorded using pulsed magnetic field up to 60 T. This has enabled to investigate the intersublattice coupling strength and its temperature dependence, a value JCo-Gd/kB = -5.3 ± 0.3 K is derived from the magnetization curves whereas one gets much larger value for JCo-Co/kB = 108 K. [ABSTRACT FROM AUTHOR]

The performance of iron-based superconductors in high magnetic fields plays an important role for their practical application. In this work, we measured the magnetostriction and magnetization of BaFe1.908Ni0.092As2 single crystals using pulsed magnetic fields up to 60 T and static magnetic fields up to 33 T, respectively. A huge longitudinal magnetostriction (of the order of 10–4) was observed in the direction of twin boundaries. The magnetization measurements evidence a high critical-current density due to strong bulk pinning. By using magnetization data with an exponential flux-pinning model, we can reproduce the magnetostriction curves qualitatively. This result shows that the magnetostriction of BaFe1.908Ni0.092As2 can be well explained by a flux-pinning-induced mechanism. [ABSTRACT FROM AUTHOR]

Nonequilibrium processes are probed by ultrasound waves in the spin-ice material Dy2Ti2O7 at low temperatures. The sound velocity and the sound attenuation exhibit a number of anomalies versus applied magnetic field for temperatures below the "freezing" temperature of ~500 mK. These robust anomalies can be seen for longitudinal and transverse acoustic modes for different field directions. The anomalies show a broad hysteresis. Most notable are peaks in the sound velocity, which exhibit two distinct regimes: an intrinsic (extrinsic) one in which the data collapse for different sweep rates when plotted as function of field strength (time). We discuss our observations in context of the emergent quasiparticles which govern the low-temperature dynamics of the spin ice. [ABSTRACT FROM AUTHOR]

We report on measurements of the magnetization up to 7 T, of the specific heat and electrical resistivity in fields up to 14 T, and of the magnetic susceptibility in fields up to 20 T of a polycrystalline sample of Rh17S15. Our data allow us to complement the superconducting phase diagram. The existence of narrow 4 d-band states (and thus of strong electronic correlations that seem not to provide magnetic correlations) is supported by the moderately high electronic contribution to the specific heat of about 107 mJ/molK2, favoring the existence of a strong superconducting interaction. This fact, and the remarkably high upper critical field (exceeding the simple Pauli limit by a factor of two), give evidence of the uncommon nature of the superconductivity in Rh17S15. [ABSTRACT FROM AUTHOR]

Abstract: has been classified as the first tetragonal U-based Kondo insulator. Here, we present measurements of the thermal conductivity and thermopower S of high-quality single-crystalline along and perpendicular to the tetragonal c-axis, in the temperature range between 100mK and 1K, in zero field and in a magnetic field of 6T. Below 400mK, the phonon contribution to shows a behaviour for both directions that can be attributed to phonons scattered by electrons. presents a linear behaviour in the whole temperature range. S is positive along the c-axis and negative perpendicular to the c-axis. Using a one-band model the effective mass is estimated to be along and perpendicular to the c-axis, where is the free-electron mass. This indicates that has a highly anisotropic residual density of states within the pseudogap. [Copyright &y& Elsevier]

The heavy rare-earth-based Laves phases are well-studied intermetallic materials that stand out for their remarkably high magnetocaloric effects, particularly at cryogenic temperatures. In this study, we present the findings of our comprehensive investigation of cobalt Laves phases R Co 2 with R standing for erbium, holmium, dysprosium, and terbium. This includes the determination of the magnetocaloric effect by indirect methods using calorimetric and magnetization data. Furthermore, for the first time in these materials, we directly measured the adiabatic temperature change at high magnetic fields up to 20 T. The largest Δ T ad value of 17 K, we obtained for ErCo 2. Because the order of the transition significantly impacts the efficiency of thermodynamic cycles, we have also focused on determining the transition order in these materials. This was done through the application of established methods and a recently proposed quantitative criterion including the value of the local exponent n. Further, we compare our results with other materials using a straightforward material-based figure of merit - the temperature-averaged entropy change (TEC). Our results demonstrate the great potential of these materials for applications such as for magnetic hydrogen liquefaction. • A comprehensive experimental study was conducted on the magnetocaloric effect in Laves phases RCo2 (R=Er, Ho, Dy, Tb). • Directly obtained adiabatic temperature changes in RCo2 at high magnetic fields up to 20 T are provided for the first time. • Calorimetric, magnetization, and directly obtained data are in good agreement between each other. • The study highlights the potential of these materials in applications such as magnetic hydrogen liquefaction. [ABSTRACT FROM AUTHOR]

We have studied the magnetic and magnetocaloric response of MnFe 4 Si 3 to pulsed and static magnetic fields up to 50 T. We determine the adiabatic temperature change ΔT ad directly in pulsed fields and compare to the results of magnetization and specific heat measurements in static magnetic fields. The high ability of cycling even in fields μ 0 H = 50 T confirms the high structural stability of MnFe 4 Si 3 against field changes, an important property for applications. The magnetic response to magnetic fields up to μ 0 H = 35 T shows that the anisotropy can be overcome by fields of approx. 4 T. • Magnetic and magnetocaloric properties of single crystalline MnFe 4 Si 3 have been studied in pulsed and static fields. The adiabatic temperature change ∆T ad determined directly in pulsed fields is in good agreement to the results of magnetization and specific heat measurements in static magnetic fields. • Direct measurement of the adiabatic temperature change using pulsed magnetic fields is an excellent technique for the evaluation of the magnetocaloric effect, as it provides nearly adiabatic conditions and an experimental situation that is close to the one present in real applications. • The compound MnFe 4 Si 3 shows high cyclability even in very high fields which confirms its high structural stability against field changes, an important property for applications. [ABSTRACT FROM AUTHOR]