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Two 1D CN-bridged assemblies: the nearly straight Li2[Ni(cyclam)][Nb(CN)8]·7.5H2O (1) chains and the zigzag-shaped Li2[Ni(cyclam)][Nb(CN)8]·2H2O (2) chains, are obtained in the reaction between [Ni(cyclam)]2+ and [Nb(CN)8]4− in warm concentrated LiCl water solution. Both compounds are composed of alternating bimetallic Ni(II)–Nb(IV) chains and contain incorporated lithium cations, which compensate the negative charge of the coordination skeleton. The straight chain 1 (Ni–Nb–Ni angle = 153.2°) can be reversibly dehydrated under dry nitrogen flow at room temperature to an intermediate dihydrate phase 1d and further transformed to the zigzag-shaped chain 2 (Ni–Nb–Ni angle = 86.6°) by annealing at 150 °C. The process can be reversed by exposure to high humidity at room temperature, upon which 2 is converted back to 1. This water sorption-induced breathing effect is accompanied by changes in magnetic properties, most notably reflected in different values of saturation magnetization and critical field of metamagnetic transition, which indicate that both intra- and inter-chain interactions are affected by the structure reorganization. [ABSTRACT FROM AUTHOR]

The multiferroic YMn0.5Cr0.5O3 (YMCO) compound possesses magnetic phases that are debatable for their origin in intrinsic and extrinsic attributes. To extract the contribution of the polycrystalline disorder as well as determine the effect of structural modifications and epitaxial strain on the magnetic properties, we have formed YMCO bulk in polycrystalline pellet and powder forms, and epitaxial thin films with a wide range of compressive and tensile strains. The temperature and field dependent magnetization of polycrystals discards the possibility of magnetization reversal and unveils the presence of multidomain states with soft and hard characters in powder form. The epitaxial YMCO films possess an extraordinary structural control of their magnetic properties, as the tuning of compressive strain results in an increase of 4–5 factors of magnitude in the saturation magnetic moment. This strain engineering further allows a tuning of the magnetic property from spin frustration/short-range ordering to the long-range ordering, which also induces a rare phenomenon of sharp step-like metamagnetic transition. The implementation of magneto-terahertz time-domain spectroscopy on this system does not show the manifestation of any magnon/electromaganon resonance typical of a magnetoelectric phase, thus suggesting either a very weak or lack of coupling between magnetic and electric ordered parameters in polycrystalline YMCO. This study resolves some longstanding issues on the magnetic and magnetoelectric phases in addition to the epitaxial control of large magnetization and metamagnetic transition being potentially relevant in several aspects of spintronics applications. [ABSTRACT FROM AUTHOR]

This study investigates the structural and magnetic properties of α–CoV2O6 and Cr doped α–CoV2O6 samples synthesized using a wet chemical method. X-ray diffraction (XRD) measurements and analysis indicate that α–CoV2O6 forms in a monoclinic crystal structure, with lattice parameters a = 9.26 Å, b = 3.50 Å, c = 6.62 Å, β = 111.42°, and α = γ = 90°. The magnetic properties of the compounds were probed using a vibrating sample magnetometer (VSM), by measuring the temperature, T, field, μ0H, and time, t, dependence of magnetization, M. The compounds take on an antiferromagnetic (AFM) order at 0.1 T, with an enhancement of the magnetization below 6.5 K. Cr doping resulted in an enhancement of magnetization below TN. M(μ0H) isotherms show metamagnetic transitions with a 1/3 magnetization plateau for both samples. A large hysteresis is observed for fields less than 5 T and is attributed to frozen metastable, irreversible states. M(T) data at 2.5 T and 5 T shows that the metamagnetic transitions take both compounds from an AFM to an intermediate ferrimagnetic (FI) state and ferromagnetic (FM) state at high fields. No significant changes in TN were observed with Cr doping. Zero-field-cooled (ZFC) and field-cooled (FC) bifurcation was observed for fields between 1 T and 3 T, attributed to spin-glass-like freezing of the samples at TSG. The spin-glass behaviour of the samples was confirmed using the Gabay-Toulouse (G-T) line and M(t) curves. [ABSTRACT FROM AUTHOR]

This study investigates the structural and magnetic properties of α–CoV2O6 and Cr doped α–CoV2O6 samples synthesized using a wet chemical method. X-ray diffraction (XRD) measurements and analysis indicate that α–CoV2O6 forms in a monoclinic crystal structure, with lattice parameters a = 9.26 Å, b = 3.50 Å, c = 6.62 Å, β = 111.42°, and α = γ = 90°. The magnetic properties of the compounds were probed using a vibrating sample magnetometer (VSM), by measuring the temperature, T, field, μ0H, and time, t, dependence of magnetization, M. The compounds take on an antiferromagnetic (AFM) order at 0.1 T, with an enhancement of the magnetization below 6.5 K. Cr doping resulted in an enhancement of magnetization below TN. M(μ0H) isotherms show metamagnetic transitions with a 1/3 magnetization plateau for both samples. A large hysteresis is observed for fields less than 5 T and is attributed to frozen metastable, irreversible states. M(T) data at 2.5 T and 5 T shows that the metamagnetic transitions take both compounds from an AFM to an intermediate ferrimagnetic (FI) state and ferromagnetic (FM) state at high fields. No significant changes in TN were observed with Cr doping. Zero-field-cooled (ZFC) and field-cooled (FC) bifurcation was observed for fields between 1 T and 3 T, attributed to spin-glass-like freezing of the samples at TSG. The spin-glass behaviour of the samples was confirmed using the Gabay-Toulouse (G-T) line and M(t) curves. [ABSTRACT FROM AUTHOR]

Large magnetization jumps (MJs) can realize an avalanched flip of the spin structure from a low spin state (antiferromagnetic) to a high spin state (ferromagnetic) and has potential applications in spin devices. Here, we report giant MJs in dual-antiferromagnetic hematite-ilmenite (Fe2O3)0.1(FeTiO3)0.9 (HI-9) solid solution. The obtained intensity of MJs (the ratio of an abrupt change in magnetization to saturation magnetization) increases to 53.3%, which is about twice as much as previously reported values in HI-9. These unusually large MJs are achieved by intentionally introducing multiscale distortions with high-stress compression deformation. Both experiments and Monte Carlo simulations demonstrate that the increase in MJs' intensity originates from the tunable atomic-scale and nano-scale distortions induced by crystal strain energy during the deformation process. Our findings provide an approach to modulate metamagnetic transitions and may inspire fresh ideas for creating high-performance antiferromagnetic materials. [ABSTRACT FROM AUTHOR]

Effects of Sc substitution on metamagnetic transitions for erbium are investigated for Er1−xScx ($0.0\le x \le0.2$) to find optimal magnetocaloric materials for high-efficient magnetic refrigeration using static bias magnetic field. We observed that the Néel temperature decreases with increasing $x$. The magnetocaloric properties are discussed in comparison with the previously reported phase diagram. We found that the metamagnetic transitions from the antiferromagnetic-like configurations to the ferromagnetic-like ones are accompanied with relatively large magnetic entropy changes for all the samples. The obtained knowledge would be helpful to further study on magnetic refrigeration utilizing the features of metamagnetic transitions. [ABSTRACT FROM AUTHOR]

The magnetization measurements have been performed to bring out the magnetic and magnetocaloric properties of polycrystalline DySe2 system synthesized by solid state reaction and duly characterized by X-ray diffraction. Room temperature XRD analysis reveals tetragonal structure for this system. Temperature-dependent magnetization measurements display paramagnetic to antiferromagnetic transition at the Neel temperature (TN) ~ 4.7 K. The TN exhibits systematic decrease with increase in magnetic field. Isothermal magnetization data exhibits a field-induced meta-magnetic transition below TN. The onset magnetic field for the meta-magnetic transition decreases with increase in temperature. Arrot plot analysis reveals that both the paramagnetic to antiferromagnetic and the meta-magnetic transitions are first order in nature. Isothermal magnetic entropy change (ΔS) with temperature exhibits negative nonmonotonic behavior with a peak (ΔSmax) for field change ΔH > 10 kOe. The value of ΔSmax is found to be ~ 11.7 J/kg-K for a field change of 70 kOe. [ABSTRACT FROM AUTHOR]

The magnetization measurements have been performed to bring out the magnetic and magnetocaloric properties of polycrystalline DySe2 system synthesized by solid state reaction and duly characterized by X-ray diffraction. Room temperature XRD analysis reveals tetragonal structure for this system. Temperature-dependent magnetization measurements display paramagnetic to antiferromagnetic transition at the Neel temperature (TN) ~ 4.7 K. The TN exhibits systematic decrease with increase in magnetic field. Isothermal magnetization data exhibits a field-induced meta-magnetic transition below TN. The onset magnetic field for the meta-magnetic transition decreases with increase in temperature. Arrot plot analysis reveals that both the paramagnetic to antiferromagnetic and the meta-magnetic transitions are first order in nature. Isothermal magnetic entropy change (ΔS) with temperature exhibits negative nonmonotonic behavior with a peak (ΔSmax) for field change ΔH > 10 kOe. The value of ΔSmax is found to be ~ 11.7 J/kg-K for a field change of 70 kOe. [ABSTRACT FROM AUTHOR]

We have investigated the magnetic and magnetocaloric properties of ferromagnetic superconductor Ru(Sr1–xLax)2GdCu2O8 (x=0–0.10) by magnetization and heat capacity measurements. RuSr2GdCu2O8 shows onset of superconductivity at around 46K, which coexists with the weak ferromagnetic ordering of the RuO2 moments and the antiferromagnetic ordering of the Gd moments. Both superconducting RuSr2GdCu2O8 and non-superconducting Ru(Sr0.9La0.1)2GdCu2O8 compounds exhibit a large magnetic entropy change due to the field-induced metamagnetic transition. The maximum values of entropy change, adiabatic temperature change, and refrigerant capacity are ~15.5 J kg–1 K–1, ~14 K, and ~125 J kg–1, respectively, for a field change of 0–7T for both the compounds. These magnetocaloric parameters also have reasonably good values for a moderate field change (2–3T), therefore, fulfilling the necessary conditions for refrigeration in the low-temperature region. [ABSTRACT FROM AUTHOR]

We have investigated the magnetic and magnetocaloric properties of ferromagnetic superconductor Ru(Sr1–xLax)2GdCu2O8 (x=0–0.10) by magnetization and heat capacity measurements. RuSr2GdCu2O8 shows onset of superconductivity at around 46K, which coexists with the weak ferromagnetic ordering of the RuO2 moments and the antiferromagnetic ordering of the Gd moments. Both superconducting RuSr2GdCu2O8 and non-superconducting Ru(Sr0.9La0.1)2GdCu2O8 compounds exhibit a large magnetic entropy change due to the field-induced metamagnetic transition. The maximum values of entropy change, adiabatic temperature change, and refrigerant capacity are ~15.5 J kg–1 K–1, ~14 K, and ~125 J kg–1, respectively, for a field change of 0–7T for both the compounds. These magnetocaloric parameters also have reasonably good values for a moderate field change (2–3T), therefore, fulfilling the necessary conditions for refrigeration in the low-temperature region. [ABSTRACT FROM AUTHOR]

The vision to manipulate and control magnetism with light is driven on the one hand by fundamental questions of direct and indirect photon-spin interactions, and on the other hand by the necessity to cope with ever growing data volumes, requiring radically new approaches on how to write, read and process information. Here, we present two complementary experimental geometries to access the element-specific magnetization dynamics of complex magnetic systems via ultrafast magneto-optical spectroscopy in the extreme ultraviolet spectral range. First, we employ linearly polarized radiation of a free electron laser facility to demonstrate decoupled dynamics of the two sublattices of an FeGd alloy, a prerequisite for all-optical magnetization switching. Second, we use circularly polarized radiation generated in a laboratory-based high harmonic generation setup to show optical inter-site spin transfer in a CoPt alloy, a mechanism which only very recently has been predicted to mediate ultrafast metamagnetic phase transitions. [ABSTRACT FROM AUTHOR]

Magnetic phase diagrams of the metamagnetic shape memory alloys Ni 50-x Co x Mn 31.5 Ga 18.5 (x = 9 and 9.7) were produced from high-field magnetization measurements up to 56 T. For both compounds, magnetic field induced martensitic transformations are observed at various temperatures below 300 K. Hysteresis of the field-induced transformation shows unconventional temperature dependence: it decreases with decreasing temperature after showing a peak. Magnetic susceptibility measurement, microscopy, and X-ray diffraction data suggest a model incorporating the magnetic anisotropy and Zeeman energy in two variants, which qualitatively explains the thermal and the magnetic field history dependence of the hysteresis in these alloys. Image, graphical abstract [ABSTRACT FROM AUTHOR]

• Curie and Weiss constants vary with composition regularly but not in a mean-field way. • The location of a susceptibility maximum varies modestly until nickel content is high. • The magnetization and its hysteresis evolves regularly with composition. • The location of a metamagnetic transition varies regularly with composition. • The thermoremanent magnetization is largest at the composition extremes. Effects of disorder, frustration and low dimensional character occur in mixed magnetic Co 1−x Ni x Cl 2 ·H 2 O, examined by dc magnetization and susceptibility measurements across the composition range. The pure components are quasi-one-dimensional antiferromagnets ordering at 15.0 K (Co) and 5.6 5 K (Ni), with susceptibility maxima at 16.2 and 8.4 K respectively; a spin glass transition also appears in the cobalt system near 8 K. In each compound weaker antiferromagnetic interchain exchange interactions supplement dominant ferromagnetic exchange along MCl 2 MCl 2 M... chemical and structural chains. High temperature magnetic susceptibilities are analyzed to yield Curie and Weiss constants in χ M = C/(T − θ). Regular but not mean-field composition dependences appear for C and θ. The former is not linear and the latter displays a minimum near x = 0.30. Notable is a susceptibility maxima varying in location only weakly from x = 0.10 to x = 0.70, decreasing markedly only for higher x. Magnetization isotherms evolve regularly as x varies, with systematic composition dependences of a metamagnetic transition field and hysteresis through x = 0.70. A qualitative change in the isotherms occurs for x = 0.90, but substantial curvature still appears with smaller but definite hysteresis. A thermoremanent magnetization is seen in all mixtures, and is largest for the composition extremes. Thus, nonequilibrium magnetic behavior characteristic of the cobalt component, in contrast to the more conventional nickel component, occurs even when the latter is present in strong majority. [ABSTRACT FROM AUTHOR]

The manganite Nd 0.15 Ca 0.85 MnO 3 crystallizes in GdFeO 3 -type, orthorhombic structure (space group Pnma) at 300 K and orders antiferromagnetically at 112 K (T N). Magnetization-field (M-H) isotherms indicate metamagnetic transition at temperatures below T N. However, metamagnetism does not lead to saturation in magnetization. The magnetization value at 2 K in 140 kOe field is only 0.4 μ B /f.u. The isothermal magnetic entropy change (ΔS m) has been calculated using the M-H data and inverse magnetocaloric effect is observed around T N and the maximum value of ΔS m is ∼12.2 J kg−1K−1 at 107.5 K for 140 kOe field change. Powder neutron diffraction study in zero applied field reveals monoclinic distortion of Nd 0.15 Ca 0.85 MnO 3 crystal lattice and antiferromagnetic ordering of Mn sublattice in ac -plane with wave vector K = [1/2, 0, 1/2] at 125 K. From the neutron data, the Mn magnetic moment value at 3 K is found to be 2.54 μ B. Electrical resistivity increases tremendously below T N to an insulating state and shows thermal hysteresis near T N in zero field. Large magnetic fields drive insulator to metal-like transition and negative colossal magnetoresistance of about 70% is realized at 50 K in 70 kOe field and that could be due to the field-induced order. • Simultaneous magnetic and crystal structural transitions are observed in electron doped Nd 0.15 Ca 0.85 MnO 3. • Inverse magnetocaloric effect occurs in the vicinity of the first order antiferromagnetic transition (T N). • The metamagnetic transition below T N likely drives the colossal magnetoresistance. [ABSTRACT FROM AUTHOR]

Structural and magnetic properties of GdGa are investigated using the combined results of X-ray diffraction and magnetization. DC magnetization measurements were carried out on as-cast and annealed specimens. Although, no considerable changes in the crystal parameters are observed by the effect of annealing, the change in the magnetic behavior is discernible. The low-temperature state is found to be simple antiferromagnetic with prevailing ferromagnetic exchange interactions in the paramagnetic state. The mismatch between the experimentally obtained effective magnetic moment of Gd in GdGa and the effective magnetic moment of Gd + 3 is attributed to the presence of finite-sizable spin–orbit coupling. Moreover, the weakly correlated antiferromagnetic low-temperature ground state can be easily tuned to the ferromagnetic state through a spin-flop process. [ABSTRACT FROM AUTHOR]

We have synthesized the new YbMn 6−y Fe y Sn 6 alloys (y = 0.25, 0.50, 0.75, and 1.00) and investigated their crystal and magnetic properties using X-ray diffraction and magnetization measurements. All alloys crystallize in the orthorhombic HoFe 6 Sn 6 type of structure (Immm) with cell parameters shrinking upon increasing the iron content. In these alloys, the T = Mn/Fe sublattice orders ferromagnetically near T C  ∼ 270 K. Yb does not magnetically order and its valency is estimated to be υ ∼ 2.6–2.7 from lattice constants. Guidelines are proposed to go through the Yb magnetic instability and the quantum phase transition associated with. The YbMn 5.75 Fe 0.25 Sn 6 compound is a pure ferromagnet over the whole ordered temperature range, as the ternary YbMn 6 Sn 6 parent compound, while the richer Fe alloys evolve upon cooling towards a low-magnetization state through a first-order transition. A field-induced metamagnetic transition allows recovering the ferromagnetic alignment and the alloys present maximal magnetizations of close magnitude (∼12.5 µ B /f.u. at 5 K). [ABSTRACT FROM AUTHOR]

We report specific heat, magnetization, magnetoresistance, and neutron diffraction measurements of single crystals of ErNi 3 Ga 9 . This compound crystalizes in a chiral structure with space group R 32 . The erbium ions form a two–dimensional honeycomb structure. ErNi 3 Ga 9 displays antiferromagnetic order below 6.4 K. We determined that the magnetic structure is slightly amplitude–modulated as well as antiferromagnetic with q = ( 0 , 0 , 0.5 ) . The magnetic properties are described by an Ising–like model in which the magnetic moment is always along the c –axis owing to the large uniaxial anisotropy caused by the crystalline electric field effect in the low temperature region. When the magnetic field is applied along the c –axis, a metamagnetic transition is observed around 12 kOe at 2 K. ErNi 3 Ga 9 possesses crystal chirality, but the antisymmetric magnetic interaction, the so-called Dzyaloshinskii–Moriya (DM) interaction, does not contribute to the magnetic structure, because the magnetic moments are parallel to the DM–vector. [ABSTRACT FROM AUTHOR]

The magnetic and magnetocaloric measurements are reported for Ni49.9Mn37.03Sb12.3Fe0.77. The application of magnetic field was found to result in a shift of characteristic temperatures of the martensitic transformation (MT) by 0.7 K/T. Direct measurements of magnetocaloric effect (MCE) were employed to evaluate potential of this alloy for magnetic refrigeration. Peak values of MCE in magnetic field of 5 T were determined to be ~ −0.6 K in the interval of MT, and ~1 K in the vicinity of Curie temperature. [ABSTRACT FROM PUBLISHER]

The derivation is presented of the Clausius–Clapeyron relation (CCR) in the second order of expansion of free energy potential on the change of temperature and magnetic field on the example of Ni–Mn–In Heusler alloys with the first-order metamagnetostructural phase transition (FOMMSPT), which can be treated as thermoelastic structural transition: austenite—martensite merging with metamagnetic transition: ferromagnet–antiferromagnet. It is shown that the second-order CCR describes satisfactory the nonlinear shift in the characteristic temperatures of the FOMMSPT in magnetic fields up to 25 T. It qualitatively and quantitatively explains the observed nonlinear dependence of the characteristic temperatures and the hysteresis of FOMMSPT including its elimination in some compositions of the Ni–Mn–In Heusler alloys under sufficiently high magnetic field. [ABSTRACT FROM AUTHOR]

R 3 AlC x (R = Ce, Pr and Nd; x = 0–1) series has been synthesized by arc melting. Rietveld analysis of x-ray powder diffraction reveals cubic (Pm-3m) structure. A Kondo temperature T K ~ 1 K is estimated for Ce 3 AlC 0.65 from the susceptibility and resistivity data. Magnetic susceptibility measurements indicate antiferromagnetic (AFM) order for R = Pr (x = 0.8 and 1) and Nd (x = 0.6, 0.8 and 1) and ferromagnetic (FM) for Nd 3 Al. Metamagnetic behaviour in the magnetization curve indicates complex magnetic structure. Band structure calculations indicate growth of a pseudo-gap in the density of states (DOS) from Ce 3 AlC to Pr 3 AlC to Nd 3 AlC. The DOS calculations predict a metallic behaviour which is consistent with the resistivity measurements. [ABSTRACT FROM AUTHOR]

In order to exemplify, we consider a finite itinerant- electron metamagnetic gas at sufficiently low absolute temperature so that relevant new results are obtained. In fact, we study key aspects related to derive the electronic energy of the abovementioned metamagnetic gas in relation to the Fermi levels of the spin-up and spin-down electron bands and in relation to the exchange energy and magnetic susceptibility. Within an unprecedented mathematical--physics approach, the abovementioned electronic energy is reinterpreted by defining it as an averaged quantity from the corresponding nonrelativistic, time-independent, Schrödinger equation with two-band energy-eigenvalue spectrum. In parallel, a matrix formulation is presented. [ABSTRACT FROM AUTHOR]

The magnetic properties of little examined CoBr 2 •2H 2 O and new CoBr 2 •H 2 O and CoBr 2 •D 2 O are studied. Curie-Weiss fits, χ M =C/(T-θ), yield θ of −9.9, 9.4 and 10.0 K, respectively, over a 30–80 K linear range for each. Higher temperature data are fit assuming two moderately separated low lying Kramers doublets, with exchange accounted for in a mean-field approximation. Susceptibility maxima appear at 9.5, 15.4 and 15.5 K, with χ max of 0.163, 0.375 and 0.435 emu/mol, respectively. Antiferromagnetic ordering is estimated to occur at 9.0, 13.7 and 13.8 K, in the same order. The ratio T c /T max is 0.95, 0.89 and 0.89, respectively, suggesting little low dimensional magnetic character in singly hydrated systems. Data at lower temperatures for the dihydrate are fit with an antiferromagnetic 3D-Ising model. For singly hydrated systems the large size of χ max prevents this; weakened interchain antiferromagnetic interactions yield enhanced susceptibility maxima. Magnetization data exhibit field induced transitions near 13.5 kG for the dihydrate, and near 6.5 kG for singly hydrated systems with enhanced hysteresis. These transitions are interpreted as metamagnetic in nature. [ABSTRACT FROM AUTHOR]

The study of the structural and magnetic properties of LaFe 12 B 6 under high pressure has been performed by combining angle-dispersive x-ray powder diffraction at room temperature up to 14 GPa and magnetization measurements up to 1 GPa. At ambient pressure, the itinerant-electron compound LaFe 12 B 6 exhibits an antiferromagnetic ground state below T N =36 K. It is demonstrated that the antiferromagnetic state can be transformed into a ferromagnetic state via a field-induced first-order metamagnetic transition accompanied with a large magnetic hysteresis. The x-ray diffraction measurements under pressure reveal that the ambient pressure crystal structure of LaFe 12 B 6 is preserved up to 14 GPa with a decrease of the unit cell parameters. A compressibility value of κ=4.90 10 −3 GPa −1 has been determined. The application of an external pressure leads also to the progressive decrease of the Néel temperature d T N /d P =−4.5 K GPa −1 . In addition a large pressure effect on the critical field μ 0 H cr of the metamagnetic transition, dμ 0 H cr / dP =24 T GPa −1 , was discovered. This clearly indicates the crucial role of volume effect on the itinerant-electron metamagnetic transition. [ABSTRACT FROM AUTHOR]

• The magnetic decoupling between the Cu1 ferromagnetic chain and the Cu2 antiferromagnetic chain has been revealed. • The high-field magnetization presents a metamagnetic transition at 1.7 T and a half-saturated ferromagnetic (FM)-like magnetization process. • The antiferromagnetic resonances of the antiferromagnetically coupled Cu1 FM chains were observed, showing the presence of significant magnetic anisotropy. The high-field magnetization and electron spin resonance (ESR) are reported for the two-dimensional triangular-lattice antiferromagnet Cu 2 (OH) 3 HCO 2. The compound has an antiferromagnetic (AFM) order at T N = 4.9 K with the Curie-Weiss temperature θ CW = − 3.8 K. The high-field magnetization up to 50 T exhibits a metamagnetic transition at 1.7 T followed by a half-saturated ferromagnetic (FM)-like magnetization process, showing the magnetic decoupling between the Cu1 FM chain and the Cu2 AFM chain. The unsaturated magnetization at 50 T serves as an evidence of much larger AFM exchange in the Cu2 chain. The temperature-dependent ESR spectra are in line with the development of magnetic correlations and AFM ordering. The observed ESR modes below T N originate from the AFM resonances of the antiferromagnetically coupled Cu1 FM chains. The zero-field gap of 111 GHz and the zero-frequency field of 2.4 T suggest the presence of significant magnetic anisotropy. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dy doping was made on La based cuprate francisite compounds. • Metamagnetic transition and weak spin reorientation transition were observed. • Interestingly metamagnetic transition was observed from temperature dependent magnetization measurement also beside usual field dependent magnetization measurement. • The entire process of metamagnetic transition were explored from spin flop and spin flip mechanisms. • Dy doping enriched magnetism and the reasons were interpreted from spin dependent energy splitting scheme of Cu, Dy and La (only vacant 5d orbital). Study of La-based cuprate francisite (LaCufr), an analogue compound of Cu 3 Bi(SeO 3) 2 O 2 Cl, is interesting due to the interplay of competing magnetic interactions in this geometrically frustrated layered compound. The motivation is to investigate the role of rare earth metals with 4f electrons on Cu2+ ions with 3d electrons, i.e., to study a complex 3d-4f interaction. In this regard, pristine, 5, and 10 at% (atomic percentage) Dy doped La-based cuprate francisite [Cu 3 La 1-x Dy x (SeO 3) 2 O 2 Cl; x = 0, 0.05, and 0.1] compounds were synthesized. Structural (X-ray diffraction i.e. XRD), electronic (X-ray absorption near edge structure i.e. XANES) and magnetic properties were investigated. XRD and XANES ensure phase purity and indicate dopant Dy atoms are more or less substitutionally incorporated at the La site. Magnetic properties were highlighted by unconventional magnetic hysteresis due to spin reorientation transition (SRT) and field-induced meta -magnetic transition (MMT) below 15 K. The signature of MMT was also observed from a temperature dependent magnetization (M−T) study, which is unique. The process of field dependent magnetization has been explored with a spin flop and spin flip transition. Dy doping enhances hysteresis and overall magnetization. The reason for this enhancement has been interpreted as identifying micro-interactions using an energy splitting scheme. [ABSTRACT FROM AUTHOR]

Magnetic energy conversion systems based on magnetocaloric effect promise to be an efficient and eco-friendly alternative to widespread gas cooling systems. Progress in this field initiates an active search for high-performance magnetic refrigerants with suitable characteristics. Among various caloric materials, rare-earth multi-principal element alloys are of particular interest to achieve these purposes. Since structure and properties in these materials strongly depend on synthesis conditions and fabrication prehistory, these issues need to be considered for each multi-element systems. This study is aimed to address structure formation, magnetic and magnetocaloric properties in ScGdTbDyHo high-entropy alloy fabricated under different conditions. We analyze the liquid and solid phases in this system using the ab initio molecular dynamics simulations and find that the alloy has a strong tendency to form a single-phase solid solution. Within the experimental study, as-cast, rapidly quenched, thermally annealed and severely cold-deformed alloy samples have been examined. We have found that all the fabricated specimens are single-phase hexagonal close-packed solid solutions characterized by different density of structural defects. The magnetic measurements reveal a complex magnetic structure in these materials. The Neel point in the studied alloys varies in the range of 139–144 K. A field-induced metamagnetic transition from antiferromagnetic to ferromagnetic state is observed in the alloy samples at all temperatures below the Neel point. In the magnetically ordered state, all the materials demonstrate large coercive force, reaching 4 kOe. Despite of the magnetic hysteresis, the alloys demonstrate the largest values of relative cooling power (920–984 J/kg at 5 T magnetic field) among similar rare-earth high-entropy systems reported so far. Analysis of the experimental results obtained for the alloy samples fabricated under different synthesis conditions allows us to conclude that there is a correlation between structural defectiveness and refrigerant capacity in this rare-earth system. • The liquid and solid phases in the system are analyzed with the ab initio molecular dynamics simulations. • The fabricated materials are single-phase solid solutions with HCP crystalline structure. • The alloys exhibit a complex magnetic structure and a pronounced field-induced metamagnetic transition. • The relative cooling power in the alloys reaches values of 920–984 J/kg at 5 T magnetic field. • A correlation between structural defectiveness and the refrigerant capacity is revealed. [ABSTRACT FROM AUTHOR]

We investigate the nature of ultrasharp metamagnetic transitions in La 5/8-y Nd y Ca 3/8 MnO 3 manganites. These compounds change from a low temperature ferromagnetic metallic state at low Nd doping to a charge-ordered antiferromagnetic insulator for high Nd content. At an intermediate doping a phase-separated state is established. At low temperatures (∼2 K), an avalanche-like field-induced metamagnetic transition is observed, where the entire compound changes abruptly from one phase to the other. The behavior of this ultrasharp transition is investigated using magnetization and specific heat measurements. We found a first order transition in the specific heat associated with discontinuous jumps in the magnetization. A strong increase of the sample temperature is simultaneously observed. The results are interpreted in terms of latent heat released from the field-induced enhancement of the ferromagnetic fraction, triggering the avalanche process. [ABSTRACT FROM AUTHOR]

We have investigated the temperature and magnetic field dependence of magnetization ( M ), specific heat ( C p ), and relative sample length change ( Δ L / L 0 ) for understanding the field-induced metamagnetic transitions in quasi-one-dimensional monoclinic ( α phase) and triclinic ( γ phase) CoV 2 O 6 spin chains. With the application of external magnetic field, a sharp peak emerges in C p ( T ) below T N = 15 K in α phase and a hump-like feature appears above T N = 6.5 K in γ phase due to the field-induced ferrimagnetic and ferromagnetic transitions, respectively. Strong field dependence of linear thermal expansion and large positive magnetostriction have been observed in α phase. Though magnetization data indicate strong spin–orbit coupling for both phases, other measurements show that this effect is very weak for the γ phase. [ABSTRACT FROM AUTHOR]

We show that it is possible to replace in Gd 2 In some amount of In by X=Al, Ga, Sn and Pb to obtain Gd 2 In 1− x X x samples after melting. The magnetic and magnetocaloric properties of the Gd 2 In 0.8 X 0.2 intermetallic compounds have been investigated through dc magnetization measurements. We evidence that the substitution of Al and Ga for In barely changes the Curie temperature T C but decreases the second magnetic transition temperature T ′ which corresponds to the transition from a ferromagnetic to an antiferromagnetic state. On the other hand, the substitution of Sn and Pb for In strongly increases T C and changes the nature or even suppresses the transition at lower temperature. This magnetic behavior gives rise to an interesting way to tune the Curie temperature near room temperature without diluting the Gd network and thus to modify the magnetocaloric effect in Gd 2 In 1− x X x compounds. [ABSTRACT FROM AUTHOR]

We here report the magnetization, M , and specific heat, C , of Nd 3 NiGe 2 , which crystallizes in the orthorhombic Gd 3 NiSi 2 -type structure. Nd ions occupy three nonequivalent sites in a unit cell. Upon cooling, magnetization divided by magnetic field, M / B , increased sharply at the Curie temperature, T C , of 87 K and below 40 K. The former result indicates that the increase in M / B observed at T C is due to the long-range ferromagnetic order. The increase below 40 K is derived from a short-range correlation because of the absence of clear anomaly in C ( T ) . At 10 K and 2 K, the values of M undergo metamagnetic transitions. The value of magnetic specific heat divided by temperature shows a shoulder-like anomaly at around 20 K, which is attributed to antiferromagnetic behavior. Furthermore, two peaks in C ( T ) were observed at 4.5 K and 3.8 K, and these peaks occurred at lower temperatures in the presence of a magnetic field. This behavior is typical of materials with antiferromagnetic order. These observations are attributed to the competition between ferromagnetic and antiferromagnetic interactions, which is a result of the three nonequivalent Nd sites. [ABSTRACT FROM AUTHOR]

We report longitudinal ultrasound velocity measurements for magnetic fields up to 33 T applied parallel to the a axis of the heavy electron compound UPt3. A characteristic dip in the sound velocity at the metamagnetic critical field Hc = 20 T, reported in earlier work, is reproduced and shown to be independent of temperature at very low temperatures. We show that the single energy scale model [Shivaram et al., Phys. Rev. B 89, 241107(R) (2014)] captures the observed key features of the field dependence in the sound velocity shift δvs. The shift δvs at Hc is found to be inversely dependent on temperature above ~ 3 K and assumes a fixed value at low T. This "saturation" in δvs below ~ 3 K is accounted for by level broadening of the uranium spin states. [ABSTRACT FROM AUTHOR]

To clarify the electronic, lattice, and magnetic contribution to the inverse magnetocaloric effect (IMCE) in the metamagnetic shape-memory alloy Ni45Co5Mn50-xInx, magnetization, magnetocaloric effect, and specific-heat measurements were carried out in a wide range of fields and temperatures. The IMCEs of Ni45Co5Mn36.7ln13.3 were directly measured as adiabatic temperature changes in pulsed fields of up to 15 T. A maximum temperature decrease of -12.8 K was observed. The low-temperature specific heats in both the austenitic and the martensitic phases of Ni45Co5Mn36.5 ln13.5 were measured by using steady fields. Through analyses of the data, the entropy changes in charge (1.2 J/kg K), spin (-2 9 J/kg K), and lattice (51 J/kg K) sectors were individually evaluated. The result demonstrates the dominant role of the lattice sector in inverse MCEs in this material. [ABSTRACT FROM AUTHOR]

[Display omitted] • The charge ordering (CO) phase in La 0.5- x Bi x Ca 0.5 MnO 3 is enhanced with Bi3+ doping. • The enhancement of CO phase is explained by the s-p hybridization model. • Pulsed high magnetic fields up to 50 T were used to study the CO phase melting. • H C - T phase diagrams of La 0.5- x Bi x Ca 0.5 MnO 3 (0 ≤ x ≤ 0.2) were obtained. La 0.5- x Bi x Ca 0.5 MnO 3 (x = 0, 0.05, 0.1 and 0.2) compounds have been prepared to study the effects of Bi3+ substitution on the structure, magnetic and magnetotransport properties. Experimental results show that Bi3+ dopants have induced a distinct lattice distortion and phase separated state in which the long range ferromagnetic order turns into short range ferromagnetic clusters, and the charge ordering/antiferromagnetism and ferromagnetic clusters coexist in the system. Bi3+ doping induced disorders lead to the presence of a Griffith-like phase. The hybridization between Bi3+-6s orbitals and O2–-2p orbitals produces a localization of O2–-2p electrons and lattice distortion, which plays an important role in favoring charge ordering state and multiple magnetic ordering. The charge ordering antiferromagnetic collapses into ferromagnetic phase through a metamagnetic transition with applying a sufficiently high magnetic field. A T - H C phase diagram was determined based on the magnetization and electrical transport measurements, in which the phase boundary is figured out. [ABSTRACT FROM AUTHOR]

We report on peculiar magnetic-field-induced metamagnetic transitions in the antiferromagnetic itinerant-electron compound La 0·9 Ce 0·1 Fe 12 B 6. Below 8 K, the first magnetization curves display multiple steep jumps generating a staircase-like shape. Whereas the magnetization of La 0·9 Ce 0·1 Fe 12 B 6 varies smoothly with the external applied magnetic field at T ≥ 8 K. We further show that this staircase effect is extremely sensitive to the thermomagnetic history of the sample. • Antiferromagnetic ground state. • Staircase-like metamagnetic transitions. • Huge magnetic field hysteresis. • Strong magnetic-field-driven irreversibility. [ABSTRACT FROM AUTHOR]

We report a magnetization study down to 1.7 K for the trilayered ruthenate Sr4Ru3O10 for magnetic fields applied within the ab plane. Our measurements reveal that the metamagnetic jump appearing in the isothermal magnetization curves below TM=68 K is actually composed of two consecutive metamagnetic transitions, where the increase in the magnetization due to the second transition is roughly one third of the overall metamagnetic jump. We show that the metamagnetic critical fields for these two transitions increase as the temperature decreases, and that their difference has a weak temperature dependence that opens up in the proximity of the critical region near TM. We discuss the origin of this double metamagnetic transition being due to either the ordering of the Ru 4d magnetic moments in the two inequivalent crystallographic Ru sites or to the presence of two van Hove singularities in the near-Fermi-level density of states. [ABSTRACT FROM AUTHOR]

Large magnetocaloric effect (MCE) and magnetoresistance (MR) together with negligible hysteresis loss have been observed in ErNiSi compound, which undergoes metamagnetic transition at low temperatures. Magnetization, heat capacity, and resistivity measurements confirm the metamagnetic transition. Both MCE and MR follow H² dependence in the paramagnetic regime. The maximum value of isothermal entropy change (ΔSM) and MR for a field change of 50 kOe are found to be 19.1 J/kg K and ~34%, respectively. Large MCE with negligible magnetic hysteresis loss could make this material promising for low temperature magnetic refrigeration. [ABSTRACT FROM AUTHOR]

Magnetic properties of the layered itinerant system Sr1-xCaxCo2P2 were investigated under a magnetic field up to 70 T. As for the exchange-enhanced Pauli paramagnetic metal SrCo2P2, the magnetization curve shows two characteristic anomalies. The high-field anomaly corresponds to an itinerant-electron metamagnetic transition (IEMT), while the low-field one is small and broad without any obvious hystereses just as the crossover phenomenon between different energy states. Such a successive transition in the magnetization curve cannot be explained by the conventional phenomenological theory for IEMT based upon the Landau expansion of the magnetic free energy, but by the extended Landau expansion theory dealing with two distinguishable energy states. In the systematical study on Sr1-xCaxCo2P2, furthermore, the metamagnetic transition field decreases and goes to zero as x increases up to 0.5, indicating that the ferromagnetic quantum critical point exists at x ~ 0.5. [ABSTRACT FROM AUTHOR]