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The phase content and sequence, the crystal structure, and the magnetic properties of perovskite solid solutions of the (1-y)BiFeO3-yBiZn0.5Ti0.5O3 series (0.05 ≤ y ≤ 0.90) synthesized under high pressure have been studied. Two perovskite phases, namely the rhombohedral R3c and the tetragonal P4mm, which correspond to the structural types of the end members, BiFeO3 and BiZn0.5Ti0.5O3, respectively, were revealed in the as-synthesized samples. The rhombohedral and the tetragonal phases were found to coexist in the compositional range of 0.30 ≤ y ≤ 0.90. Magnetic properties of the BiFe1-y[Zn0.5Ti0.5]yO3 ceramics with y < 0.30 were measured as a function of temperature. The obtained compositional variations of the normalized unit-cell volume and the Néel temperature of the BiFe1-y[Zn0.5Ti0.5]yO3 perovskites in the range of their rhombohedral phase were compared with the respective dependences for the BiFe1-yB3+ yO3 perovskites (where B3+ = Ga, Co, Mn, Cr, and Sc). The role of the high-pressure synthesis in the formation of the antiferromagnetic states different from the modulated cycloidal one characteristic of the parent BiFeO3 is discussed. [ABSTRACT FROM AUTHOR]

• Encapsulation of the magnetic quasi-two-dimensional system Cu(en)(H 2 O) 2 SO 4 in SBA-15. • Weakening of magnetic correlations after encapsulation. • Analysis of the EPR line shape confirmed significant magnetic dilution. In this work, we present an experimental study to find the optimal way of encapsulation of the magnetic quasi-two-dimensional system Cu(en)(H 2 O) 2 SO 4 (en = ethylenediamine = C 2 H 8 N 2) in mesoporous silica SBA-15 with hexagonal pore morphology with a pore size of 5 nm. Our main goal is to achieve the most significant possible degree of pore filling and to study the effect of encapsulation of complex Cu(en)(H 2 O) 2 SO 4 in SBA-15 silica on the magnetic properties of the studied complex by means of electron paramagnetic resonance (EPR) and magnetization measurements. It was found that the adsorption equilibrium during the adsorption of the Cu(en)(H 2 O) 2 SO 4 complex from the solution to SBA-15 was reached after only 24 h, and the samples prepared by adsorption for a longer time (72 h, 14 days) did not show an increased amount of the loaded complex. The degree of pore filling represents around 60 % of the total volume of internal pores. The analysis of temperature dependence of susceptibility, the field dependence of magnetization, and EPR spectra showed that due to the encapsulation of Cu(en)(H 2 O) 2 SO 4 complex in mesoporous silica, the magnetic correlations between Cu(II) ions are significantly weakened, yielding paramagnetic behavior in the studied system. [ABSTRACT FROM AUTHOR]

The analysis of specific heat, magnetic susceptibility and magnetization identified the studied compound Cu[C 6 H 2 (COO) 4 ][H 3 N–(CH 2) 2 –NH 3 ]·3H 2 O as a quasi-two-dimensional S = 1/2 Heisenberg antiferromagnet on the rectangular lattice with the intrachain coupling J 1 /k B ≈ 7.39 K and the interaction ratio R ≈ 0.44. A phase transition to a magnetically ordered state was observed in zero magnetic field at T N = 1.28 K. The analysis of magnetic specific heat in non-zero magnetic fields revealed features characteristic of the field-induced Berezinskii-Kosterlitz-Thouless phase transition theoretically predicted for ideal two-dimensional magnets. The electron paramagnetic resonance studies of Cu[C 6 H 2 (COO) 4 ][H 3 N–(CH 2) 2 –NH 3 ]·3H 2 O revealed the increase of g x and g y and decrease of g z below 25 K due to the presence of dipolar coupling and the exchange anisotropy. The upturn of linewidth appearing below 30 K can be ascribed to the development of intralayer magnetic correlations. • The system represents S = 1/2 Heisenberg antiferromagnet on the rectangular lattice. • A phase transition to a magnetically ordered state occurs in B = 0 T at T N = 1.28 K. • The field-induced Berezinskii-Kosterlitz-Thouless phase transition was observed. [ABSTRACT FROM AUTHOR]

A simple one-step mechanically induced route was used for synthesis of Gd 2 MoO 6 (GMO). Single-phase with disordered structure was obtained after 12 ​h of milling. Elemental analysis revealed continuous decomposition of ammonium orthomolybdate. SEM-EDS (energy dispersive X-ray spectrometry) analysis confirmed a homogeneous distribution of Gd, Mo, and O with the atomic ratio 22.2:8.6:69.2% corresponding to Gd 1.998 Mo 0.774 O 6.228. Aside from conventional X-ray diffraction, we here paid an effort to obtain the information about the local structure of our GMO by 155Gd ​Mössbauer spectroscopy. The analysis of temperature dependence of magnetic susceptibility and field dependence of magnetization of GMO was confirmed to be similar to those of the mechano/thermally synthesized Gd 2 MoO 6 mentioned in our previous study (Tóthová et al., 2019) [1]. Small deviations suggest the presence of nonmagnetic unreacted materials in the starting mixture used in the present mechanosynthesis. We would like to emphasize that the present simplified synthesis without annealing steps leads to GMO with very good quality in the terms of magnetic properties. Mechanochemical reaction of milled mixture up to 12 ​h at 500 ​rpm. On the left: view on the grinding/milling chamber containing milled mixture together with grinding/milling balls. On the right: 155Gd ​Mössbauer spectrum of mechanosynthesized product, i.e. Gd 2 MoO 6. [Display omitted] • Preparation of nanocrystalline Gd 2 MoO 6 by one-step mechanosynthesis. • 155Gd ​Mössbauer spectra of mechanosynthesized product. • Analyzing the quality of mechanosynthesized material by magnetic measurements. [ABSTRACT FROM AUTHOR]

We report on single-crystal growth, and crystal structure of CuMn 3 As 2 and Cu 2 Mn 4 As 3 compounds. Magnetic properties of Cu 2 Mn 4 As 3 were studied in temperature range between 2 and 400 K. The single crystals were prepared from bismuth flux and characterized by means of single crystals diffraction, electron-microprobe analysis, magnetic and resistivity measurements. Crystal structures of CuMn 3 As 2 and Cu 2 Mn 4 As 3 were determined by synchrotron radiation x-ray diffraction experiments at 100 K. The CuMn 3 As 2 and Cu 2 Mn 4 As 3 crystallize in an orthorhombic structure with very similar lattice parameters. Magnetic and resistivity measurements on Cu 2 Mn 4 As 3 suggest existence of long range magnetic order below 315 K with another magnetic transition at 45 K. [ABSTRACT FROM AUTHOR]

The comprehensive study reported herein provides compelling evidence that anion templates are the main driving force in the formation of two novel nanoscale lanthanide hydroxide clusters, {Gd38(ClO4)6} ( 1) and {Gd48Cl2(NO3)} ( 2), characterized by single-crystal X-ray crystallography, infrared spectroscopy, and magnetic measurements. {Gd38(ClO4)6}, encapsulating six ClO4− ions, features a cage core composed of twelve vertex-sharing {Gd4} tetrahedrons and one Gd⋅⋅⋅Gd pillar. When Cl− and NO3− were incorporated in the reaction instead of ClO4−, {Gd48Cl2(NO3)} is obtained with a barrel shape constituted by twelve vertex-sharing {Gd4} tetrahedrons and six {Gd5} pyramids. What is more, the cage-like {Gd38} can be dynamically converted into the barrel-shaped {Gd48} upon Cl− and NO3− stimulus. To our knowledge, it is the first time that the linear M-O-M′ fashion and the unique μ8-ClO4− mode have been crystallized in pure lanthanide complex, and complex 2 represents the largest gadolinium cluster. Both of the complexes display large magnetocaloric effect in units of J kg−1 K−1 and mJ cm−3 K−1 on account of the weak antiferromagnetic exchange, the high NGd/ MW ratio (magnetic density), and the relatively compact crystal lattice (mass density). [ABSTRACT FROM AUTHOR]

Two kinds of inorganic gadolinium(III)-hydroxy 'ladders', [2× n] and [3× n], were successfully trapped in succinate (suc) coordination polymers, [Gd2(OH)2(suc)2(H2O)] n ⋅ 2 n H2O ( 1) and [Gd6(OH)8(suc)5(H2O)2] n ⋅4 n H2O ( 2), respectively. Such coordination polymers could be regarded as alternating inorganic-organic hybrid materials with relatively high density. Magnetic and heat capacity studies reveal a large cryogenic magnetocaloric effect (MCE) in both compounds, namely (Δ H=70 kG) 42.8 J kg−1 K−1 for complex 1 and 48.0 J kg−1 K−1 for complex 2. The effect of the high density is evident, which gives very large volumetric MCEs up to 120 and 144 mJ cm−3 K−1 for complexes 1 and 2, respectively. [ABSTRACT FROM AUTHOR]

The magnetic properties of the hybrid materials formed by coordination compounds and clay minerals represent one of the main challenges in material science. The investigation of the intercalation of tris (2,2′-bipyridine)nickel(II) cations [Ni(bpy) 3 ]2+ present in the solution with chloride anions into synthetic saponite (Sap) was carried out by direct exchange of the sodium ions by nickel(II) complex. The final intercalated [Ni(bpy) 3 ]2+ saponite complex was characterized by powder X-ray diffraction (XRD), infrared (IR) spectroscopy, carbon and thermal analysis, and for the first time also by magnetic measurements. The carbon analysis proved a full replacement of Na+ with [Ni(bpy) 3 ]2+ cations. Furthermore, significant increase of the d 001 value of the intercalated saponite confirmed the presence of the [Ni(bpy) 3 ]2+ in Sap interlayers. Only limited effect of the saponite layers on the ring C-H or skeletal vibrations of the [Ni(bpy) 3 ]2+ complex was observed. The thermal stability of the [Ni(bpy) 3 ]2+ increased after its intercalation into saponite. The magnetic properties of the [Ni(bpy) 3 ]2+ saponite complex revealed similar magnetic response as the starting compound [Ni(bpy) 3 ]Cl 2 · n H 2 O suggesting that the local surroundings of the Ni(II) atoms in [Ni(bpy) 3 ]2+ intercalated into saponite remained unchanged. • The intercalation of [Ni(bpy) 3 ]2+ complex into synthetic saponite was accomplished. • The increase of d-value confirmed its presence in the saponite interlayers. • Thermal stability of the complex increased after its intercalation. • Magnetic properties of [Ni(bpy) 3 ]2+ remained unchanged after intercalation into saponite. [ABSTRACT FROM AUTHOR]