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Comprehensive Summary: The precise syntheses of transition–rare‐earth metal clusters with desired structures remain a great challenge. Herein, by utilizing SO42– anion released by in‐situ decomposition of sodium dodecyl sulfate (SDS) as a template, a series of novel high‐nuclearity 3d‐4f clusters, formulated as [Ni24Pr22(μ3‐OH)31(pida)24(SO4)4(NO3)9(CH3COO)3]·Br4·(NO3)11·16H2O·25CH3OH (1, H2pida = N‐phenyliminodiacetic acid), [Ni24Nd22(μ3‐OH)31(pida)24(SO4)4(NO3)9(CH3COO)3]·Br4·(NO3)11·14H2O·24CH3OH (2) and [Ni24Gd22(μ3‐OH)36(bida)24(SO4)7(NO3)3(CH3COO)3]·(SO4)·Br4·(NO3)4·31H2O·32CH3OH (3, H2bida = N‐benzyliminodiacetic acid), have been successfully isolated. X‐ray crystal structure analyses reveal that all the cationic {Ni24RE22} cores in 1—3 possess a ball‐like structure with C3v symmetry, and can be viewed as consisting of an inner {RE22} core and an outer {Ni24} shell. From 1 and 2 to 3, due to the lanthanide contraction effect, the coordination numbers for rare‐earth metal centers in {RE22} are different, resulting in different number of SO42– and NO3– anions to support and stabilize the skeleton structures. Meanwhile, the magnetic properties of complexes 1—3 were also studied. The result revealed that complexes 1—3 show antiferromagnetic/ferrimagnetic interactions, and 3 exhibits magneto‐caloric effect at ultralow temperatures with a maximum –ΔSm (magnetic entropy change) value of 33.03 J·kg−1·K−1 at 3.0 K and 7 T. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The precise syntheses of transition–rare‐earth metal clusters with desired structures remain a great challenge. Herein, by utilizing SO42– anion released by in‐situ decomposition of sodium dodecyl sulfate (SDS) as a template, a series of novel high‐nuclearity 3d‐4f clusters, formulated as [Ni24Pr22(μ3‐OH)31(pida)24(SO4)4(NO3)9(CH3COO)3]·Br4·(NO3)11·16H2O·25CH3OH (1, H2pida = N‐phenyliminodiacetic acid), [Ni24Nd22(μ3‐OH)31(pida)24(SO4)4(NO3)9(CH3COO)3]·Br4·(NO3)11·14H2O·24CH3OH (2) and [Ni24Gd22(μ3‐OH)36(bida)24(SO4)7(NO3)3(CH3COO)3]·(SO4)·Br4·(NO3)4·31H2O·32CH3OH (3, H2bida = N‐benzyliminodiacetic acid), have been successfully isolated. X‐ray crystal structure analyses reveal that all the cationic {Ni24RE22} cores in 1—3 possess a ball‐like structure with C3v symmetry, and can be viewed as consisting of an inner {RE22} core and an outer {Ni24} shell. From 1 and 2 to 3, due to the lanthanide contraction effect, the coordination numbers for rare‐earth metal centers in {RE22} are different, resulting in different number of SO42– and NO3– anions to support and stabilize the skeleton structures. Meanwhile, the magnetic properties of complexes 1—3 were also studied. The result revealed that complexes 1—3 show antiferromagnetic/ferrimagnetic interactions, and 3 exhibits magneto‐caloric effect at ultralow temperatures with a maximum –ΔSm (magnetic entropy change) value of 33.03 J·kg−1·K−1 at 3.0 K and 7 T. [ABSTRACT FROM AUTHOR]

The capability of bis(dioxolene) ligands to access multiple redox states makes them ideal candidates to tune the electronic properties of metal complexes, for example to achieve valence tautomerism (VT). In this study, a family of dinuclear cobalt complexes have been isolated with the bridging bis(dioxolene) thean− ligand in the cat2−‐cat2−, cat2−‐SQ⋅− and SQ⋅−‐SQ⋅− states (cat2−=catecholate, SQ⋅−=semiquinonate): [{CoIII(tpa)}2(theacat−cat)](PF6)2 (1), [{CoIII(tpa)}2(theacat−SQ)](PF6)3 (2), and [{CoIII(tpa)}2(theaSQ−SQ)](PF6)4 (3) (theaH4=2,3,6,7‐tetrahydroxy‐9,10‐dimethyl‐9,10‐dihydro‐9,10‐ethanoanthracene, tpa=tris(2‐pyridylmethyl)amine). Multi‐technique analysis confirms that 1, 2 and 3 adopt low spin‐CoIII containing {CoIII‐cat‐cat‐CoIII}, {CoIII‐cat‐SQ‐CoIII} and {CoIII‐SQ‐SQ‐CoIII} states, respectively. Compound 1 undergoes thermally‐induced {CoIII‐cat‐cat‐CoIII} ⇌ {CoIII‐cat‐SQ‐CoII} VT in the solid‐ and solution‐states above 300 K, involving high spin‐CoII. This interconversion is contrary to expectations, as tpa typically stabilizes low spin‐CoIII‐catecholate. Compound 2 is mixed‐valence class II/II–III, indicating a localized electronic structure, with electron transfer faster than the EPR and solvent rearrangement timescales, but slower than the infrared timescale. Compound 3 exhibits strong antiferromagnetic exchange. The overlap between the dioxolene π‐orbitals in thean− increases the accessibility of the cat2−‐SQ⋅− state, resulting in VT for 1. This study demonstrates that thean− can be isolated in multiple oxidation states in metal complexes, which is promising for applications in magnetic materials. [ABSTRACT FROM AUTHOR]

Abstract As a 1.8 nm ZnSe nanocrystal is progressively doped with 1%, 5%, and 10% Fe, it shows a progressive change in its magnetic properties from a superparamagnetic FM‐dominated exchange type to an onset of AFM exchange with evidence of spin frustration. Magnetization measurements allow to obtain exchange coupling constants that are compared to the results of a Broken‐Symmetry Density Functional Theory (BS‐DFT) model of a doped (ZnSe)34 cluster. DFT shows a capability to reproduce the experimental pattern of the increasing influence of AFM exchange as doping concentration increases. The material phase segregates at the edges where strained rhombic surface sites are the preferred doping sites of iron. Large concentrations of iron leads to the formation of Fe clusters and complex exchange patterns that result in spin frustration in some iron trimers but none in the others. The spin frustration of these complex systems by assuming mirror symmetry of the sites when fitting by using BS‐DFT formalism is classified and analyzed. While some individual J constants obtained have significant errors, the averaged exchange constants are generally in good agreement with our experimental data.

A family of polyoxo(alkoxo)lanthanide cluster {Ln15} (Ln = Eu (1), Gd (2), Tb (3)) was successfully isolated via a simple hydrolysis reaction of lanthanide metal ions in the presence of tricine ligands. X-ray diffraction analyses revealed that {Ln15} displayed a wheel-like structure with a µ5-chloride anion as a template. Interestingly, each analog showed distinctive functions based on the different Ln(III) ions. Complexes 1 and 3 in the solid state emitted the characteristic fluorescence of Eu(III) or Tb(III). The fluorescence lifetimes of the 5D0 excited state for 1 and the 5D4 excited state for 3 were tested, and the values were 890 and 250 μs, respectively. Meanwhile, gadolinium analog 2 exhibited a magneto-caloric effect at ultralow temperatures with a maximum −ΔSm value of 29.9 J·kg−1·K−1 at 3 K and 7 T.

[Display omitted] • A simple method of high temperature ignition to metalorganics was successfully used to synthesize composites of NiCo 2 O 4 , NiO, and Co 3 O 4. • Through the introduction of a magnetic field tuning method during the fabrication process, NiCo 2 O 4 , NiO, and Co 3 O 4 nanoparticles are arranged closely in epoxy resin. This modification enhances the magnetic exchange interactions within the material, thereby improving both dielectric loss and magnetic loss characteristics. As a result, the minimum reflection loss RL values is up to −45.11 dB with an effective bandwidth of 4 GHz. • This paper presents a straightforward method to heighten the microwave absorption performance of NiCo 2 O 4 by modifying the macroscopic order and degree. A simple method of high-temperature ignition to metalorganics was successfully used to synthesise composites of NiCo 2 O 4 , NiO and Co 3 O 4. A detailed investigation of the composite's microwave absorption properties revealed the magneto-alignment effect. By closely arranging NiCo 2 O 4 , NiO and Co 3 O 4 nano-particles in epoxy resin, the magnetic exchange is strengthened under the influence of a magnetic field. The sample without magnetic alignment, S 0 , exhibited poor absorption efficiency with reflection loss (RL) values hardly reaching − 10 dB across a frequency range of fixed and different thicknesses (2–18 GHz). In comparison, the oriented composite exhibited higher permittivity and permeability, particularly in the high-frequency range. Considering the improved impedance matching and reasonable adjustment of dielectric and magnetic losses, the microwave absorbing performance of the oriented composite substantially improved in the 10–14 GHz range. The minimum RL is reduced to − 45.11 dB with an effective bandwidth of 4 GHz. Herein, we present a straightforward method to increase the microwave absorption performance of NiCo 2 O 4 by modifying the macroscopic order and degree. [ABSTRACT FROM AUTHOR]

The consequences of non‐uniform exchange in magnetic systems are reported. The quantum mechanical exchange interaction between spins is responsible for the phenomenon of magnetic order, and is generally considered to be uniform across bulk magnetic systems. Partly inspired by the Dzyaloshinskii‐Moriya interaction—also known as antisymmetric exchange—a linearly varying exchange interaction is used along a magnetic strip as a route to spatial inversion symmetry‐breaking. It is found that, in addition to asymmetric modes and localization, spatially varying exchange can be used to design nonreciprocal magnetic signal excitation at frequencies that are tunable. Moreover, the authors' work predicts nonreciprocity to occur across a vast range of frequencies up to hundreds of GHz. Such spin wave engineering is a key area of ongoing research in the fields of magnonics and spintronics, which are expected to enable the next generation of wireless communication technology and information processing. Analogous nonreciprocity is expected to occur in other wave systems with gradient properties. [ABSTRACT FROM AUTHOR]

In this article, we apply the two-mode vibronic model to the study of the dimeric molecular mixed-valence cell for quantum cellular automata. As such, we consider a multielectron mixed valence binuclear d² - d¹-type cluster, in which the double exchange, as well as the Heisenberg-Dirac-Van Vleck exchange interactions are operative, and also the local ("breathing") and intercenter vibrational modes are taken into account. The calculations of spin-vibronic energy spectra and the "cell-cell"-response function are carried out using quantum-mechanical two-mode vibronic approach based on the numerical solution of the dynamic vibronic problem. The obtained results demonstrate a possibility of combining the function of molecular QCA with that of spin switching in one electronic device and are expected to be useful from the point of view of the rational design of such multifunctional molecular electronic devices. [ABSTRACT FROM AUTHOR]

Using the first-principles calculations, we investigate the structural, electronic, and magnetic properties of 3d transition metal (TM) (TM = Co, Cu, Mn, Fe, and Ni) atoms substitutional doping of SnSe monolayer. Magnetism is observed for Co, Mn, Fe, and Ni doping. In particular, Mn- and Fe-substituted systems exhibit large magnetic moment of 5.0 and 4.0μB at a very low impurity concentration. Then, we study the magnetic coupling in these two substituted systems. The magnetic coupling between two Mn atoms prefers to antiferromagnetic (AFM) owing to the super exchange between d states of two Mn atoms. Interestingly, both AFM and ferromagnetic (FM) coupling are observed in two-Fe-doped systems. Due to the strong spin–orbit coupling between Fe-3d and Se-4p, a long-range FM interaction is found in the Fe-substituted system. Our results demonstrate potential applications of TM-substituted SnSe for spintronics and magnetic storage devices.

The effect of the double exchange in a square-planar mixed-valence dn+1 - dn+1 - dn - dn-type tetramers comprising two excess electrons delocalized over four spin cores is discussed. The detailed analysis of a relatively simple d2 - d2 - d1 - d1-type tetramer shows that in system with the delocalized electronic pair the double exchange is able to produce antiferromagnetic spin alignment. This is drastically different from the customary ferromagnetic effect of the double exchange which is well established for mixed-valence dimers and tetramers with one excess electron or hole. That is why the question "Can double exchange cause antiferromagnetic spin alignment?" became the title of this article. As an answer to this question the qualitative and quantitative study revealed that due to antiparallel directions of spins of the two mobile electrons which give competitive contributions to the overall polarization of spin cores, the system entirely becomes antiferromagnetic. It has been also shown that depending on the relative strength of the second-order double exchange and Heisenberg-Dirac-Van Vleck exchange the system has either the ground localized spin-triplet or the ground delocalized spin-singlet. [ABSTRACT FROM AUTHOR]

In this work, based on structural and magnetic phase transition temperatures estimated theoretically from the first principles, the concentration phase diagram for Fe 100 − x Al x ( 15.625 ≤ x ≤ 31.25 at.%) was plotted. Structural phase transition temperatures for the experimentally observed crystal structures were obtained from the structural optimization. It is shown that for x = 28.125 at.% L1 2 -like phase with slight distortions is energetically favorable. The ground state energy and magnetic moments of Fe 75 Al 25 with different structures were calculated within GGA and GGA+U approaches. It is shown that in the case of GGA+U approximation, L1 2 phase becomes more stable compared with D0 3 . The Curie temperatures were estimated from mean field approximation and Monte Carlo simulations using ab initio calculated exchange coupling constants. Both structural and magnetic phase transition temperatures are found in qualitative agreement with the experiment. Depending on Al concentration, five different sequences of phase transitions are observed in the phase diagram. [ABSTRACT FROM AUTHOR]

Here we present the synthesis, structure and magnetic properties of complexes of general formula (Mn)(Me2NH2)4][Mn3(μ-L)6(H2O)6] and (Me2NH2)6[M3(μ-L)6(H2O)6] (M = CoII, NiII and CuII); L−2 = 4-(1,2,4-triazol-4-yl) ethanedisulfonate). The trinuclear polyanions were isolated as dimethylammonium salts, and their crystal structures determined by single crystal and powder X-ray diffraction data. The polyanionic part of these salts have the same molecular structure, which consists of a linear array of metal(II) ions linked by triple N1-N2-triazole bridges. In turn, the composition and crystal packing of the MnII salt differs from the rest of the complexes (with six dimethyl ammonia as countercations) in containing one Mn+2 and four dimethyl ammonia as countercations. Magnetic data indicate dominant intramolecular antiferromagnetic interactions stabilizing a paramagnetic ground state. Susceptibility data have been successfully modeled with a simple isotropic Hamiltonian for a centrosymmetric linear trimer, H = −2J (S1S2 + S2S3) with super-exchange parameters J = −0.4 K for MnII, −7.5 K for NiII and −45 K for CuII complex. The magnetic properties of these complexes and their easy processing opens unique possibilities for their incorporation as magnetic molecular probes into such hybrid materials as magnetic/conducting multifunctional materials or as dopant for organic conducting polymers.

In this article, we apply the two-mode vibronic model to the study of the dimeric molecular mixed-valence cell for quantum cellular automata. As such, we consider a multielectron mixed valence binuclear d2−d1–type cluster, in which the double exchange, as well as the Heisenberg-Dirac-Van Vleck exchange interactions are operative, and also the local (“breathing”) and intercenter vibrational modes are taken into account. The calculations of spin-vibronic energy spectra and the “cell-cell”-response function are carried out using quantum-mechanical two-mode vibronic approach based on the numerical solution of the dynamic vibronic problem. The obtained results demonstrate a possibility of combining the function of molecular QCA with that of spin switching in one electronic device and are expected to be useful from the point of view of the rational design of such multifunctional molecular electronic devices.

Heterometallic 3d‐4f complexes are being investigated, for some time, as being useful in molecular magnetism, particularly as single‐molecule magnets (SMMs). This interest is primarily because of the possibility of an increased ligand‐mediated super‐exchange phenomenon between the 3d and 4f metal ions. Such an interaction, apart from bestowing a favorable ground‐state spin to the complex, also assists in reducing quantum tunneling of magnetization that is widely prevalent in SMMs making them to lose magnetization. However, assembling both 3d as well as 4f ions using same ligand system is challenging and involves the design of multi‐site coordination ligands with specific coordination compartments for the 3d and the 4f metal ions while at the same time allowing these disparate metal ions to be linked to each other through a bridging ligating atom. This review presents a summary of the 3d‐4f complexes primarily derived from the author's work while alluding to important examples from the literature. We also provide an outlook for the future design of such complexes. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The tetranuclear complex of Cu(II) with a tetraporphyrin sheet was studied computationally. • This complex demonstrates the open-shell singlet ground state. • The exchange coupling constant was calculated for the neighboring and opposite Cu(II) ions. • The superexchange mechanism explains the antiferromagnetic behaviour of this complex. Abstract Owing to the fact that weakly-coupled Cu(II) complexes are potentially applicable in the fields of spintronics and single-molecule magnets we have studied one particularly conspicuous case – a tetranuclear square-planar complex of Cu(II) ions with a π-extended tetraporphyrin ligand (Tetrahedron, 2008, 64, 11433), the structural criteria of which, with very long distances between the paramagnetic centers, can sensibly define the exchange coupling constants and magnetic behaviour. We use the "broken symmetry" density functional theory formalism for various spin states (open-shell singlet, triplet and quintet states). The calculated value of the magnetic exchange integral corresponds to a very weak antiferromagnetic coupling between the neighboring Cu(II) ions ( J calc = –1.48 cm−1(calculated) J exp = −1.16 cm−1 (experiment)). The opposite Cu(II) ions are coupled ferromagnetically with an extremely small exchange constant ( j calc = 0.09 cm−1 (calculated) that corresponds to the open-shell singlet ground state of the following spin configuration ↑ ↓ ↑ ↓ . The exchange mechanism between the [Cu(n) + 4N] localized singly-occupied "magnetic" orbitals of the d xy (Cu) + 4sp 2(N) nature indicates a diffuse non-zero overlap between them on the Carbon atoms of the organic ligand. The numerical analysis of atomic spin densities and corresponding decomposition coefficients for the singly-occupied "magnetic" orbitals confirm the proposed exchange mechanism. This superexchange pathway is mediated by the in-plane sp2-hybrid orbitals of the Carbon atoms that couple four [Cu + 4N] fragments by the σ-bond system. For more detailed characterization of the target system a topological analysis of electron density distributions in the high-spin quintet states has been carried out using the Bader's method "quantum theory of atoms in molecules". [ABSTRACT FROM AUTHOR]

The effect of the double exchange in a square-planar mixed-valence dn+1−dn+1−dn−dn–type tetramers comprising two excess electrons delocalized over four spin cores is discussed. The detailed analysis of a relatively simple d2−d2−d1−d1–type tetramer shows that in system with the delocalized electronic pair the double exchange is able to produce antiferromagnetic spin alignment. This is drastically different from the customary ferromagnetic effect of the double exchange which is well established for mixed-valence dimers and tetramers with one excess electron or hole. That is why the question “Can double exchange cause antiferromagnetic spin alignment?” became the title of this article. As an answer to this question the qualitative and quantitative study revealed that due to antiparallel directions of spins of the two mobile electrons which give competitive contributions to the overall polarization of spin cores, the system entirely becomes antiferromagnetic. It has been also shown that depending on the relative strength of the second-order double exchange and Heisenberg–Dirac–Van Vleck exchange the system has either the ground localized spin-triplet or the ground delocalized spin-singlet.

Reaction of Ni(NCS)2 with different co‐ligands based on pyridine derivatives substituted in 4‐position leads to the formation of 1D coordination polymers with the composition [Ni(NCS)2(co‐ligand)2]n, in which the metal cations are coordinated octahedrally by two S‐ and two N‐bonding thiocyanate anions as well as two neutral co‐ligands and are linked into chains by µ‐1,3‐bridging thiocyanate anions. Dependent on the nature of the co‐ligand, novel isomers with linear and corrugated chains are observed, in which the Ni cations are trans‐ or cis‐cis‐trans coordinated. This also includes a dimer and two isomeric chain compounds with 4‐chloropyridine as ligand, of which one is metastable at room‐temperature. For all these compounds, together with several additional Ni(NCS)2 chain compounds, the values of the intrachain exchange interaction J are extracted based on magnetic measurements. The values of J for 13 different Ni(NCS)2 compounds are compared with the structural results to investigate if there are some simple relations between the magnetic exchange, the metal coordination and the chain geometry. The low temperature magnetic properties of the Ni(NCS)2 dimer and the chain compounds are also discussed based on magnetic and specific heat measurements. Several isomeric Ni(NCS)2 chain compounds including a dimer were prepared, in which the Ni cations are trans‐ or cis‐cis‐trans coordinated leading to the formation of linear or corrugated chains. The magnetic properties are presented and for all the chain compounds the influence of the metal coordination and chain geometry on the magnetic exchange is discussed. [ABSTRACT FROM AUTHOR]

The coordination chemistry of multinuclear metal compounds is important because of their relevance to the multi-metal active sites of various metalloproteins and metalloenzymes. Multinuclear CuII and MnIII compounds are of interest due to their various properties in the fields of coordination chemistry, inorganic biochemistry, catalysis, and optical and magnetic materials. Oxygenbridged binuclear MnIII complexes generally exhibit antiferromagnetic interactions and a few examples of ferromagnetic interactions have also been reported. Binuclear CuII complexes are important due to the fact that they provide examples of the simplest case of magnetic interaction involving only two unpaired electrons. Two novel dioxygen-bridged copper(II) and manganese(III) Schiff base complexes, namely bis(μ-4-bromo-2-{[(3-oxidopropyl)imino]methyl}-phenolato)dicopper(II), [Cu2(C10H10BrNO2)2], (1), and bis(diaqua{4,4'-dichloro-2,2'-[(1,1-dimethylethane-1,2-diyl)bis(nitrilomethanylylidene)]diphenolato}manganese( III)) bis{μ-4,4'-dichloro-2,2'-[(1,1-dimethylethane-1,2-diyl)bis(nitrilomethanylylidene)] diphenolato}bis[aquamanganese(III)] tetrakis(perchlorate) ethanol disolvate, [Mn(C18H16Cl2N2O2)(H2O)2]2[Mn2(C18H16Cl2N2O2)2(H2O)2]-(ClO4)4μ2C2H5OH, (2), have been synthesized and single-crystal X-ray diffraction has been used to analyze their crystal structures. The structure analyses of (1) and (2) show that each CuII atom is four-coordinated, with long weak Cu…O interactions of 2.8631 (13) Å linking the dinuclear halves of the centrosymmetric tetranucelar molecules, while each MnIII atom is sixcoordinated. The shortest intra- and intermolecular nonbonding Mn…Mn separations are 3.3277 (16) and 5.1763 (19) Å for (2), while the Cu…Cu separations are 3.0237 (3) and 3.4846 (3) Å for (1). The magnetic susceptibilities of (1) and (2) in the solid state were measured in the temperature range 2-300 K and reveal the presence of antiferromagnetic spin-exchange interactions between the transition metal ions. [ABSTRACT FROM AUTHOR]

The magnetic properties of a nanoscale system are inextricably linked to its local environment. In adatoms on surfaces and inorganic layered structures, the exchange interactions result from the relative lattice positions, layer thicknesses, and other environmental parameters. Here, we report on a sample-dependent sign inversion of the magnetic exchange coupling between the three unpaired spins of an organic triradical molecule embedded in a three-terminal device. This ferro-to-antiferromagnetic transition is due to structural distortions and results in a high-to-low spin ground-state change in a molecule traditionally considered to be a robust high-spin quartet. Moreover, the flexibility of the molecule yields an in situ electric tunability of the exchange coupling via the gate electrode. These findings open a route to the controlled reversal of the magnetic states in organic molecule-based nanodevices by mechanical means, electrical gating, or chemical tailoring. [ABSTRACT FROM AUTHOR]

The magnetic properties of the solid solution YCuxMn1-xO3 have been investigated in the whole range of possible substitutions 0.30 ≤ x(Cu) ≤ 0.50. The χa.c. data showed the presence of minute amounts, undetectable by X-ray diffraction, of the antiferromagnetic Y2Cu2O5 phase, which did not interfere with the overall magnetic behavior of the solid solution. The total effective moment of the paramagnetic state decreases continuously with x(Cu). The average moment per Mn ion was estimated after subtraction of the copper contribution, giving approximately 4.4 μB, independent of the Cu concentration ; this value corresponds to the magnetic moment expected for 50 % Mn3+ and 50 % Mn4+. A paramagnetic-to-antiferromagnetic transition is observed at TNéel = 21 K, also compositional-independent. The low temperature state, studied by ZFC/FC cycles and M(H) loops, reinforce the idea of antiferromagnetic interactions in these compounds. A very small ferromagnetic component giving rise to low coercive fields of the order of 800 Oe, was present for all Cu concentrations. Additional nuclear powder diffraction measurements show no specific magnetic structure, suggesting short range interactions.Se han investigado las propiedades magnéticas de la solución sólida YCuxMn1-xO3 para todo el rango de posibles sustituciones 0.30 ≤ x(Cu) ≤ 0.50. Las medidas de susceptibilidad χa.c. señalan la presencia de ínfimas cantidades de la fase antiferromagnética Y2Cu2O5, la que no modifica las propiedades globales de la solucion sólida. El momento magnético total del estado paramagnético decrece monótonamente con x(Cu). El momento magnético promedio por ion Mn fue estimado después de sustraer la contribución del cobre, dando un valor aproximado de 4.4 μB, independiente de la concentración en cobre ; este valor corresponde al momento magnético esperado para 50 % Mn3+ y 50 % Mn4+. Una transición paramagnética hacia un estado antiferromagnético es observada a TNéel = 21 K, independiente de la composición. Los estudios a bajas temperaturas, realizados mediante ciclos ZFC/FC y de magnetización M(H), corroboran la idea de interacciones antiferromagnéticas en estos compuestos. Una pequeña componente ferromagnética es observada en los ciclos de magnetización realizados a 5K, indicando que el estado ordenado es principalmente de tipo antiferromagnético, con una componente inclinada despreciable, la que da lugar a un campo coercitivo muy pequeño (aprox. 800 Oe). Medidas preliminares por difracción de neutrones no indican ninguna estructura magnética específica, eliminando la posibilidad de interacciones de largo alcance.