Metamagnetic Behavior Research Articles

Correlations between stacked structures and weak itinerant magnetic properties of La2−xYxNi7 compounds

Hexagonal La2Ni7 and rhombohedral Y2Ni7 are weak itinerant antiferromagnet (wAFM) and ferromagnet (wFM), respectively. To follow the evolution between these two compounds, the crystal structure and magnetic properties of A2B7 intermetallic compounds (A = La, Y, B = Ni) have been investigated combining x-ray powder diffraction and magnetic measurements. The La2−xYxNi7 intermetallic compounds with 0 ⩽ x ⩽ 1 crystallize in the hexagonal Ce2Ni7-type structure with Y preferentially located in the [A2B4] units. The compounds with larger Y content (1.2 ⩽ x < 2) crystallize in both hexagonal and rhombohedral (Gd2Co7-type) structures with a substitution of Y for La in both [A2B4] and [AB5] units. Y2Ni7 crystallizes in the rhombohedral structure only. The average cell volume decreases linearly versus Y content, whereas the c/a ratio presents a minimum at x = 1 due to geometric constrains. The magnetic properties are strongly dependent on the structure type and the Y content. La2Ni7 displays a complex metamagnetic behavior with split AFM peaks. Compounds with x = 0.25 and 0.5 display a wAFM ground state and two metamagnetic transitions, the first one toward an intermediate wAFM state and the second one toward a FM state. TN and the second critical field μ0Hc2 increase with the Y content, indicating a stabilization of the AFM state. LaYNi7, which is as the boundary between the two structure types, presents a very wFM state at low field and an AFM state as the applied field increases. All the compounds with x > 1, and which contains a rhombohedral phase are wFM with TC = 53(2) K. In addition to the experimental studies, first principles calculations using spin polarization have been performed to interpret the evolution of structural phase stability for 0 ⩽ x ⩽ 2.

Structural and magnetic properties of the interstitial carbide-hydride NdScSiC0.5H0.2

We report the synthesis of the first carbide-hydride phase obtained in the family of equiatomic intermetallics RTX (R = rare earth, T = transition metal, X = p-block element) by insertion of light elements. We prepared the NdScSiC0.5H0.2 compound by solid-gas reaction, by exposing the carbide NdScSiC0.5 to 40 bars of H2 gas at 450 °C. It crystallizes in the La2Fe2Se2O3-type structure with H and C atoms occupying Nd4 tetrahedral and Nd2Sc4 octahedral interstices, respectively. The H site is only partly filled owing to the presence of Nd–C covalent bonding that prevents the formation of Nd–H bonding through antagonist effect. The carbide-hydride was characterized through magnetic measurements, specific heat and powder neutron diffraction. Remarkably, hydrogenation of the carbide provokes a quite drastic effect on the magnetic properties by changing the ground state from a ferromagnetic (TC∼70 K) to an antiferromagnetic one (TN = 10 K). The magnetic structure of NdScSiC0.5H0.2 consists of double layers of ferromagnetic Nd moments aligned along the c-axis and coupled antiferromagnetically along this axis. This magnetic structure results in a field-induced metamagnetic behaviour as pointed out by magnetisation isotherms.

Multifunctional Ni(II)-Based Metamagnetic Coordination Polymers for Electronic Device Fabrication.

The combination of two 8-aminoquinoline-based Schiff base ligands (L1 and L2) with SCN- and Ni(II) has led to the synthesis of two new one-dimensional thiocyanato-bridged coordination polymers: [Ni(L1)(NCS)2]n (1) and [Ni(L2)(NCS)2]n (2). Both compounds are isostructural and consists of regular zigzag thiocyanato-bridged chains with very weak S···S interchain interactions. The measured room-temperature conductivities of compounds 1 and 2 (7.0 × 10-5 and 2.0 × 10-5 S m-1, respectively) are indicative of semiconductor behavior which increases in the presence of photoillumination (3.5 × 10-4 and 4.9 × 10-4 S m-1, respectively). The measured I-V characteristics of compound 1 and 2 based thin film metal-semiconductor (MS) junction devices under irradiation and nonirradiation conditions show a nonlinear rectifying behavior, typical of a Schottky diode (SD). The rectification ratios (Ion/Ioff) of the SDs in the dark at ±2 V (26.96 and 31.96 for 1- and 2-based devices, respectively) increase to 44.19 and 79.42, respectively, upon light irradiation. The photoinduced behavior has been analyzed by thermionic emission theory, and to determine the diode parameters, the Cheung's method has been employed. These diode parameters indicate that compound 2 has a better performance in comparison to compound 1 and that these materials are good candidates for applications in electrochemical devices. Magnetic measurements show that both compounds present ferromagnetic Ni-Ni intrachain and weak antiferromagnetic interchain interactions. The isothermal magnetizations at 2 K show that both compounds are metamagnets with critical fields of ca. 130 mT in 1 and 90 mT in 2 at 2 K. In the ferromagnetic phase (above the critical field), both compounds exhibit a long-range ferromagnetic order with critical temperatures of around 3.5 K in 1 and 3.0 K in 2. DC and AC measurements with different applied DC fields confirm the metamagnetic behaviors and have allowed the determination of the magnetic phase diagram in both compounds.

Selective Metal-Ligand Bond-Breaking Driven by Weak Intermolecular Interactions: From Metamagnetic Mn(III)-Monomer to Hexacyanoferrate(II)-Bridged Metamagnetic Mn2Fe Trimer.

Metal-ligand coordination interactions are usually much stronger than weak intermolecular interactions. Nevertheless, here, we show experimental evidence and theoretical confirmation of a very rare example where metal-ligand bonds dissociate in an irreversible way, helped by a large number of weak intermolecular interactions that surpass the energy of the metal-ligand bond. Thus, we describe the design and synthesis of trinuclear Mn2Fe complex {[Mn(L)(H2O)]2Fe(CN)6},2- starting from a mononuclear Mn(III)-Schiff base complex: [Mn(L)(H2O)Cl] (1) and [Fe(CN)6]4- anions. This reaction implies the dissociation of Mn(III)-Cl coordination bonds and the formation of Mn(III)-NC bonds with the help of several intermolecular interactions. Here, we present the synthesis, crystal structure, and magnetic characterization of the monomeric Mn(III) complex [Mn(L)(H2O)Cl] (1) and of compound (H3O)[Mn(L)(H2O)2]{[Mn(L)(H2O)]2Fe(CN)6}·4H2O (2) (H2L = 2,2'-((1E,1'E)-(ethane-1,2-diylbis(azaneylylidene))bis(methaneylylidene))bis(4-methoxyphenol)). Complex 1 is a monomer where the Schiff base ligand (L) is coordinated to the four equatorial positions of the Mn(III) center with a H2O molecule and a Cl- ion at the axial sites and the monomeric units are assembled by π-π and hydrogen-bonding interactions to build supramolecular dimers. The combination of [Fe(CN)6]4- with complex 1 leads to the formation of linear Mn-NC-Fe-CN-Mn trimers where two trans cyano groups of the [Fe(CN)6]4- anion replace the labile chloride from the coordination sphere of two [Mn(L)(H2O)Cl] complexes, giving rise to the linear anionic {[Mn(L)(H2O)]2Fe(CN)6}2- trimer. This Mn2Fe trimer crystallizes with an oxonium cation and a mononuclear [Mn(L)(H2O)2]+ cation, closely related to the precursor neutral complex [Mn(L)(H2O)Cl]. In compound 2, the Mn2Fe trimers are assembled by several hydrogen-bonding and π-π interactions to frame an extended structure similar to that of complex 1. Density functional theoretical (DFT) calculations at the PBE1PBE-D3/def2-TZVP level show that the bond dissociation energy (-29.3 kcal/mol) for the Mn(III)-Cl bond is smaller than the summation of all the weak intermolecular interactions (-30.1 kcal/mol). Variable-temperature magnetic studies imply the existence of weak intermolecular antiferromagnetic couplings in both compounds, which can be can cancelled with a critical field of ca. 2.0 and 2.5 T at 2 K for compounds 1 and 2, respectively. The magnetic properties of compound 1 have been fit with a simple S = 2 monomer with g = 1.959, a weak zero-field splitting (|D| = 1.23 cm-1), and a very weak intermolecular interaction (zJ = -0.03 cm-1). For compound 2, we have used a model with an S = 2 monomer with ZFS plus an S = 2 antiferromagnetically coupled dimer with g = 2.009, |D| = 1.21 cm-1, and J = -0.42 cm-1. The metamagnetic behavior of both compounds is attributed to the weak intermolecular π-π and hydrogen-bonding interactions.

Origin of the metamagnetic transitions in Y1−xErxFe2(H,D)4.2 compounds

The structural and magnetic properties of Y1−xErxFe2 intermetallic compounds and their hydrides and deuterides Y1−xErxFe2H(D)4.2 have been investigated using X-ray diffraction and magnetic measurements under static and pulsed magnetic field up to 60 T. The intermetallics crystallize in the C15 cubic structure (Fd-3m space group), whereas corresponding hydrides and deuterides crystallize in a monoclinic structure (Pc space group). All compounds display a linear decrease of the unit cell volume versus Er concentration; the hydrides have a 0.8% larger cell volume compared to the deuterides with same Er content. They are ferrimagnetic at low field and temperature with a compensation point at x = 0.33 for the intermetallics and x = 0.57 for the hydrides and deuterides. A sharp first order ferromagnetic-antiferromagnetic (FM-AFM) transition is observed upon heating at TFM−AFM for both hydrides and deuterides. These compounds show two different types of field induced transitions, which have different physical origin. At low temperature (T < 50 K), a forced ferri-ferromagnetic metamagnetic transition with Btrans1 ≈ 8 T, related to the change of the Er moments orientation from antiparallel to parallel Fe moment, is observed. Btrans1 is not sensitive to Er concentration, temperature and isotope effect. A second metamagnetic transition resulting from antiferromagnetic to ferrimagnetic state is also observed. The transition field Btrans2 increases linearly versus temperature and relates to the itinerant electron metamagnetic behavior of the Fe sublattice. An onset temperature TM0 is obtained by extrapolating TFM−AFM (B) at zero field. TM0 decreases linearly versus the Er content and is 45 ± 5 K higher for the hydrides compared to the corresponding deuteride. The evolution of TM0 versus cell volume shows that it cannot be attributed exclusively to a pure volume effect and that electronic effects should also be considered.

Effect of Ni doping on martensitic transformation and magnetic properties for Co50V25Ga25∼26 Heusler alloy

ABSTRACTIn this work, we have investigated the crystalline structure, martensitic transformation (MT) and magnetic properties of Co50V25-xNixGa25 (x = 5, 6, 7, 8, 9, 12.5) together with Co50V17Ni7Ga26 Heusler alloys. It was found that the MT behavior can occur in the Ni-doped Co50V25Ga25 Heusler alloys, and the MT temperature increases with the increase of Ni doping, which can reach about room temperature as the Ni doping increases up to x = 12.5. In the temperature interval of MT, with the decrease of temperature, the metamagnetic behavior appears from the ferromagnetic austenitic phase to the paramagnetic martensitic phase in the Co50V17Ni7Ga26 Heusler alloy. As a result, the magnetocaloric effect was observed, and the calculated magnetic entropy change can achieve about 11.5 J/kg K around 94 K for the magnetic field changes of 7 T.

An effective spin Hamiltonian approach to heavy electron metamagnetism

ABSTRACTWe describe a minimal model for metamagnetism, based on a quantum spin Hamiltonian with a single energy scale. Within this model, the metamagnetic critical field is proportional to the temperature where a peak in the linear susceptibility occurs which in turn is proportional to the temperatures where the nonlinear susceptibilities also peak. The thermodynamic properties are derived in a straightforward manner and bear a striking resemblance to observations in such strongly correlated systems as heavy fermion materials. We also consider extensions of the model by including effects such as a mean field and a tilt of the quantisation axis to encompass observed deviations from a minimal metamagnetic behaviour.

Frustrated Magnetism in Triangular Lattice TlYbS2 Crystals Grown via Molten Flux.

The triangular lattice compound TlYbS2 was prepared as large single crystals via a molten flux growth technique using sodium chloride. Anisotropic magnetic susceptibility measurements down to 0.4 K indicate a complete absence of long-range magnetic order. Despite this lack of long-range order, short-range antiferromagnetic interactions are evidenced through broad transitions, suggesting frustrated behavior. Variable magnetic field measurements reveal metamagnetic behavior at temperatures ≤2 K. Complex low temperature field-tunable magnetic behavior, in addition to no observable long-range order down to 0.4 K, suggest that TlYbS2 is a frustrated magnet and a possible quantum spin liquid candidate.

A Delicate Balance between Antiferromagnetism and Ferromagnetism: Theoretical and Experimental Studies of A2 MRu5 B2 (A=Zr, Hf; M=Fe, Mn) Metal Borides.

Metal-rich borides with the Ti3 Co5 B2 -type structure represent an ideal playground for tuning magnetic interactions through chemical substitutions. In this work, density functional theory (DFT) and experimental studies of Ru-rich quaternary borides with the general composition A2 MRu5 B2 (A=Zr, Hf, M=Fe, Mn) are presented. Total energy calculations show that the phases Zr2 FeRu5 B2 and Hf2 FeRu5 B2 prefer ground states with strong antiferromagnetic (AFM) interactions between ferromagnetic (FM) M-chains. Manganese substitution for iron lowers these antiferromagnetic interchain interactions dramatically and creates a strong competition between FM and AFM states with a slight preference for AFM in Zr2 MnRu5 B2 and for FM in Hf2 MnRu5 B2 . Magnetic property measurements show a field dependence of the AFM transition (TN ): TN is found at 0.1 T for all phases with predicted AFM states whereas for the predicted FM phase it is found at a much lower magnetic field (0.005 T). Furthermore, TN is lowest for a Hf-based phase (20 K) and highest for a Zr-based one (28 K), in accordance with DFT predictions of weaker AFM interactions in the Hf-based phases. Interestingly, the AFM transitions vanish in all compounds at higher fields (>1 T) in favor of FM transitions, indicating metamagnetic behaviors for these Ru-rich phases.

Magnetic field-induced metamagnetic, magnetocaloric and pyrocurrent behaviors of Eu2CoMnO6

In this paper, the structural, transport, pyrocurrent and magnetic behaviors of Eu2CoMnO6 (ECMO) sample are reported. It was prepared by the solid-state reaction method and crystallized in monoclinic crystal structure with a space group of P21/n. A systematic study of the temperature and magnetic field-dependent susceptibility revealed a complex magnetic behavior with field-induced type-II metamagnetic phase transition of the first-order. The multiple sharp jumps in the initial magnetization curve for T < 10 K could be attributed to structural distortion related to the martensite-like strains from E*-type antiferromagnetic to ferromagnetic ordering. The metastable magnetic behavior for T ≥ 60 K is ascribed to a transformation of the low-field disordered spin glass phase to long-range ordered ferromagnetic phase, induced by critical fields. These critical fields are quite sensitive to the direction and magnitude of the field-cooling process. The temperature-dependent magnetocaloric effect with maximum value of ~3.3 J kg−1K−1 at TC ~ 123 K and the electrical transport behavior of ECMO were studied. Further, temperature dependent pyroelectric current and polarization data of ECMO are investigated.

Magnetic field dependence of the martensitic transition and magnetocaloric effects in Ni49BiMn35In15

The structural, magnetic, and magnetocaloric properties of the Bi-doped Heusler alloy Ni49BiMn35In15 have been investigated using room temperature X-ray diffraction (XRD) and magnetization measurements in a temperature interval of 5-400 K. The alloy at room temperature was found to be in a mixture of a high temperature austenite phase (AP) and a low temperature martensite phase (MP). A drastic shift in the martensitic transition temperature at the rate of 16 K/T from 197 K to lower temperatures was observed. A kinetic arrest phenomenon of the AP was observed in the magnetization and electrical resistivity measurements during field-cooled (FC) measurements at 5T. A metamagnetic behavior characterized by a jump in magnetization in the isothermal M(H) curves near TM was observed. The maximum value of the magnetic entropy change and refrigerant capacity at Curie temperature were found to be 5.5 Jkg-1K-1 and 312 Jkg-1 for μoΔH = 5T, respectively. A large magnetoresistance value of -56% was found near the martensitic transition.

Strong magnetoelastic effect in CeCo1−xFexSi as Néel order is suppressed

A very strong magnetoelastic effect in the CeCo$_{1-x}$Fe$_{x}$Si alloys is reported. The strength of the magnetostrictive effect can be tuned upon changing $x$. The moderate low-temperature linear magnetostriction observed at low Fe concentrations becomes very large ($\frac {\Delta L}{L} \left(16 T,2 K\right) =$ 3$\times$10$^{-3}$) around the critical concentration ($x_c \approx$ 0.23) at which the long-range antiferromagnetic order vanishes. Upon increasing doping through the non-magnetic region ($x > x_c$), the magnetostriction strength gradually weakens again. Remarkably the low-temperature magnetostriction at the critical concentration shows a pronounced $S$-like shape (centered at $B_m \sim$ 6 T) resembling other well-known Ce-based metamagnetic systems like CeRu$_2$Si$_2$ and CeTiGe. Unlike what is observed in these compounds, however, the field dependence of the magnetization shows only a minor upturn around $B_m$ vaguely resembling a metamagnetic behavior. The subtle interplay between magnetic order and the Kondo screening seems to originate an enhanced valence susceptibility slightly changing the Ce ions valence, ultimately triggering the large magnetostriction observed around the critical concentration.

Investigation of magnetism and magnetic structure of anti-ThCr2Si2-type Tb2O2Bi by magnetization and neutron diffraction measurements

In this study, magnetization and neutron diffraction of anti-ThCr2Si2-type Tb2O2Bi polycrystals were measured at various temperatures. The magnetization cusp at 11.1 K was confirmed to correspond to antiferromagnetic ordering with a propagation vector of [0.5 0.5 0]. In addition, a metamagnetic behavior was observed below 5.0 K. The metamagnetic behavior could be attributed to the incommensurate magnetic structure with an anomaly at 5.0 K.

Evidence of magnetoelectric effect in Co4(H2O)3(SeO3)4

A new hydrated oxoselenite(IV) Co4(H2O)3(SeO3)4 was prepared by hydrothermal synthesis. The structure was solved from single-crystal X-ray diffraction data. This new phase crystallizes in the monoclinic unit cell a = 8.9369 (4) Å, b = 8.4225(4) Å, c = 9.6197(4) Å, β = 116.8239(13)° with a non-centrosymmetric space group P21 and is isostructural to Mn4(H2O)3(SeO3)4. The 3D framework is constructed of [CoO6] octahedra forming infinite zig-zag layers and [SeO3] trigonal pyramids placed between the layers. The magnetic susceptibility measurements indicated a Curie-Weiss paramagnetic behaviour for T ≳ 50 K and an effective moment μeff = 3.9(1) μB per Co2+, which corresponds to the spin only value for high-spin Co2+ (S = 3/2). An antiferromagnetic (AF) transition is observed at TN = 9 K with metamagnetic behaviour and two field-induced states. In addition, a small remnant magnetization characteristic of a canted AF state is observed at a temperature below 7 K. Dielectric measurements performed on one single crystal showed that the dielectric properties of Co4(H2O)3(SeO3)4 change in the magnetically ordered state, suggesting magnetoelectric coupling. Specifically, in the canted AF ordered state (T < 7 K), we observed a positive magnetocapacitance effect of 4.5% under a 1 T field, confirming that Co4(H2O)3(SeO3)4 is magnetoelectric.

Metamagnetic properties in Mn0.7Mg0.3Fe2O4 ferrite

The paper deals with metamagnetic behaviour of the MnMg ferrites with stoichiometric composition Mn0.7Mg0.3Fe2O4 and is focused to structural nature of found effects. The results are a part of the materials research concerning the relationship between the types of the change from antiferomagnetic (AFM) state to ferrimagnetic (FM) state under the influence of temperature at selected magnetic field. In lower applied field under the critical value of strength Hac the increase in magnetic induction B with temperature is attributed to transition from Yafet-Kittel model to Néel's two-sublattices one. Various evaluation methods, such as e.g. thermo-magnetic analysis, magnetic Barkhausen noise analysis, and X-ray diffraction were used for obtaining experimental data. Magnetic Barkhausen noise analysis showed that mainly the domain-wall motion processes take place in the examined MnMg system.

A comparative study on phase co-existence of $$\hbox {La}_{1/4}\hbox {Pr}_{3/8}\hbox {Ca}_{3/8}\hbox {MnO}_{3}$$ in a polycrystalline bulk and thin film

We present a comparative study on phase co-existence in \(\hbox {La}_{1/4}\hbox {Pr}_{3/8}\hbox {Ca}_{3/8}\hbox {MnO}_{3}\) (LPCMO) in a polycrystalline bulk and thin film form. The X-ray diffraction results confirm the formation of single-phase polycrystalline bulk and c-axis-oriented strained epitaxial thin films on a \(\hbox {LaAlO}_{3}\) substrate. Scanning electron microscopy images show a homogeneous microstructure growth for both the bulk as well as thin film samples. The temperature dependent magnetization curves for bulk and thin film show remarkably different features indicating the presence of very different phase separation scenarios. A two-step rise and a large thermal hysteresis are observed between zero-field cooled and field-cooled magnetization plots in the bulk sample. However, the magnetization of the film shows a very small hysteresis and a negligible signature of the CO-AFM state for the same composition. The field dependent magnetization plots indicate that in a bulk form LPCMO is a soft magnet and shows a metamagnetic behaviour while in a thin film form it acts as a hard magnet and the metamagnetic behaviour is completely lost.

Multiple metamagnetism, extreme magnetoresistance and nontrivial topological electronic structures in the magnetic semimetal candidate holmium monobismuthide

Inconceivably large changes (up to 106%) of the resistivity induced by external magnetic field—a phenomenon known as the extreme magnetoresistance effect has been reported in a great number of exotic semimetals. The very recent and exciting discoveries mainly pay attention to the compounds without magnetic ground states, which appears to limit the potential growth of semimetal family. For fundamental scientific interests, introduction of spin degree of freedom would provide an almost ideal platform for investigating the correlation effect between magnetism, crystallographic structure and electric resistivity in materials. Here, we report the experimental observation of metamagnetic behaviors and transport properties of HoBi single crystals. Being a magnetic member of the rare earth monopnictide family, the magnetoresistance of HoBi is significantly modulated by the magnetic orders at low temperature, which shows a nonmonotonic increment across the successive magnetic phases and reaches 104% (9 T and 2 K) in the ferromagnetic state. Kohler’s rule predicts that more than one type of carriers dominates the transport properties. Well fitted magnetoresistance and Hall resistivity curves by the semiclassical two-band model suggest that the densities of electron and hole carriers are nearly compensated and the carrier mobilities in this compound are ultrahigh. Besides, the inverted band structures and nonzero Z2 topological invariant indicate that possible nontrivial electronic states could generate in the ferromagnetic phase of HoBi. Combining the experimental and theoretical results, it is found that the cooperative action of carrier compensation effect and ultrahigh mobility might contribute to the extreme magnetoresistance observed in the titled compound. These findings suggest a paradigm for obtaining the extreme magnetoresistance in magnetic compounds and are relevant to understand the rare-earth-based correlated topological materials.

A new three-dimensional cobalt(II) coordination polymer based on V-shaped 3,4'-oxydibenzoate: synthesis, crystal structure and magnetic properties.

A new coordination polymer (CP), namely poly[(μ-4,4'-bipyridine)(μ3-3,4'-oxydibenzoato)cobalt(II)], [Co(C14H8O5)(C10H8N2)]n or [Co(3,4'-obb)(4,4'-bipy)]n (1), was prepared by the self-assembly of Co(NO3)2·6H2O with the rarely used 3,4'-oxydibenzoic acid (3,4'-obbH2) ligand and 4,4'-bipyridine (4,4'-bipy) under solvothermal conditions, and has been structurally characterized by elemental analysis, IR spectroscopy, single-crystal X-ray crystallography and powder X-ray diffraction (PXRD). Single-crystal X-ray diffraction reveals that each CoII ion is six-coordinated by four O atoms from three 3,4'-obb2- ligands, of which two function as monodentate ligands and the other as a bidentate ligand, and by two N atoms from bridging 4,4'-bipy ligands, thereby forming a distorted octahedral CoN2O4 coordination geometry. Adjacent crystallographically equivalent CoII ions are bridged by the O atoms of 3,4'-obb2- ligands, affording an eight-membered Co2O4C2 ring which is further extended into a two-dimensional [Co(3,4'-obb)]n sheet along the ab plane via 3,4'-obb2- functioning as a bidentate bridging ligand. The planes are interlinked into a three-dimensional [Co(3,4'-obb)(4,4'-bipy)]n network by 4,4'-bipy ligands acting as pillars along the c axis. Magnetic investigations on CP 1 disclose an antiferromagnetic coupling within the dimeric Co2 unit and a metamagnetic behaviour at low temperature resulting from intermolecular π-π interactions between the parallel 4,4'-bipy ligands.

Metamagnetic anomalies in the kinetic Ising model

The effective-field theory is used to study the anomalous metamagnetic behavior of a uniaxial ferromagnetic film, which has been observed in the recent experiment Riego et al. (2017). Similar to experimental findings, the sidebands phenomena of the dynamic susceptibility have been shown in certain ranges of the bias field, as well as the amplitude and period of the oscillating magnetic field. The mechanism and precise nature of the anomalous metamagnetic behavior have been explored in detail as well. We also compare the effective-field theory results to those produced using mean-field theory and Monte Carlo simulations. We find that the analytic treatment of the effective-field theory is in good qualitative agreement with exact results of the Monte Carlo simulations.

A New One Dimensional Mn(III) Coordination Polymer Constructed by a Salicylamide Imine Multidentate Ligand: Structure, Magnetic and Luminescent Properties

A new Mn(III) coordination polymer, [MnL]n, based on a salicylamide imine multidentate ligand, 1-(2-hydroxy-benzamido)-2-(2-hydroxy-5-nitrobenzylideneamino)-ethane (H3L) was prepared. Single crystal analysis revealed that the title compound was a herringbone like Mn(III) coordination polymer where deprotonated ligand L3– acted as a pentadentate ligand with amide group being bridge to connect two Mn(III) centres. Magnetic susceptibilities indicates that [MnL]n exhibits an antiferromagnetic coupling with a long-range canted antiferromagnetic ordering and metamagnetic behavior at low temperatures. And the photophysical determination shows that [MnL]n also displays strong long life red luminescence. The results presented herein indicates [MnL]n appears to be an excellent candidate for multifunctional material as a result of its high thermal stability, interesting magnetic and luminescent properties.