The synthesis, crystal structure and magnetic properties of an oxamate-containing erbium(III) complex, namely, tetrabutylammonium aqua[N-(2,4,6-trimethylphenyl)oxamato]erbium(III)-dimethyl sulfoxide-water (1/3/1.5), (C16H36N)[Er(C11H12NO3)4(H2O)]·3C2H6OS·1.5H2O or n-Bu4N[Er(Htmpa)4(H2O)]·3DMSO·1.5H2O (1), are reported. The crystal structure of 1 reveals the occurrence of an erbium(III) ion, which is surrounded by four N-phenyl-substituted oxamate ligands and one water molecule in a nine-coordinated environment, together with one tetrabutylammonium cation acting as a counter-ion, and one water and three dimethyl sulfoxide (DMSO) molecules of crystallization. Variable-temperature static (dc) and dynamic (ac) magnetic measurements were carried out for this mononuclear complex, revealing that it behaves as a field-induced single-ion magnet (SIM) below 5.0 K.

In this paper, we report a detailed investigation of the crystal structure, magnetic, magnetocaloric, magneto-transport and electrical polarization properties of a new multiferroic material in the polycrystalline and nanocrystalline form of the Dy2MnCoO6double perovskite. Both compounds crystallized in the monoclinic structure with P21/n space group. The magnetic properties of both systems are mainly dominant ferromagnetic (FM) and weak antiferromagnetic (AFM). The FM/AFM coupling is related by the competing and combining functions of the radius and the magnetic moments of rare earth ions (i.e. 3d-4f exchange interactions). The reduction of the saturation magnetization in the isothermal magnetization curves can be explained by the existence of anti-phase boundaries and local anti-site defects in the system. Moreover, these materials hold reasonable values of magnetocaloric parameters and the absence of hysteresis makes the system a potential candidate for magnetic refrigeration. These compounds revealed two magnetic phase transitions, according to the appearance of two peaks in the temperature dependence of magnetic entropy change curves. The temperature dependent resistivity data for both the systems display semiconductor nature near room temperature and insulating like behavior at low temperature regime. The variable-range hopping conduction mechanism is used to best understand their transport mechanism. In addition, the electrical polarization loop at low temperature confirms the presence of ferroelectricity for both the studied systems. The decreases polarization under an external magnetic field evidence the weak magnetoelectric coupling. The coexistence of FM ordering with insulating behavior and ferroelectricity at low temperature promises new opportunities and improvements in next generation applications for information storage, spintronic, and sensors.

MnPt\'s exceptional stability and extremely high Néel temperature have generated a lot of interest in data storage applications. Previously, it was reported experimentally that the MnPt alloy shows ferromagnetic (FM) behavior at room temperature. In this study, the effects of partial substitution of Pt with Pd, Au, and Ag on magnetic properties is investigated using density functional theory. The stability of Mn50Pt50-xMx (M = Pd, Au, Ag, x = 6.25, 12.5, 18.75) alloys was assessed by determining their thermodynamic, magnetic, and mechanical properties. The calculated lattice constants of Mn50Pt50 agree well with available theoretical results. The Mn50Pt50-xMx alloys\' formability was assessed by measuring the thermodynamic stability using the heat of formation. It was found that B2 Mn50Pt50-xPdx alloys (0 ≤ x ≤ 18.75) are thermodynamically stable due to the negative heat of formation close to that of a pristine MnPt alloy. Based on the elasticity results, the B2 Mn50Pt50-xPdx is most likely to undergo martensitic transformation for the entire considered composition range. From the calculated values of the Poisson\'s ratio, it is shown that an increase in Pd, Ag, and Au effectively improves the ductility of the B2 Mn50Pt50-xMx compounds. It was revealed that ferromagnetism is maintained with Pd addition but significantly reduced in the case of Au and Ag. Thus, this work showed that density functional theory can be exploited to propose new possible compositions for future magnets in spintronic applications.

Up to now, the development of Ce/RE> 80% sintered permanent magnets still faces a challenge, owing to their seriously deteriorated microstructure. In this article, the Ce25.5∼31.5Nd0∼5Febal.B1.25M1.15 (wt.%) sintered magnets with Ce/RE > 80% were investigated, the roles of minor Nd substitution were explored. The typical island-like phase common existed in the grain-boundary (GB) regions of Ce2Fe14B-based SC alloys (which destroys the continuity of RE-rich GB phase), was confirmed as a tetragonal B-rich phase (fct-RE5Fe18B18), and probably generated by the peritectic reaction of \"L + Ce2Fe14B → CeFe2 + B-rich\" at 797 °C. It was found that: the deteriorated microstructures of high Ce sintered magnets were hardly improved (Nd element was not enriched in the main phase as it was expected), and the coercivity increments were far below expectations by directly adding 3-5% Nd in alloy designs. However, the GB phase distribution was more uniform and continuous, Nd-rich shells formed, and magnetic properties were remarkably promoted by blending 2% NdHx powders into the Ce27.5Nd3Febal.B1.25M1.15 (Ce27.5Nd3) magnet during JM milling, compared with the Ce25.5Nd5Febal.B1.25M1.15 (Ce25.5Nd5) magnet with similar composition. The good comprehensive magnetic properties of Hcj = 1.714 kOe, Br = 9.395 kG, and (BH)max = 11.16 MGOe have been reached in the Ce27.5Nd3+2% (NdHx) magnet (Ce accounted for 84.5 wt% of total rare earth). The present work deepens our understanding of metallurgical behavior, process/microstructure designing for Ce/RE> 80% sintered magnets, and shed a light on the large-scale utilization of Ce element in a permanent magnet.

The triangle-based magnetic subsystem of borates with the mineral norbergite structure M3BO6 (M = Fe, Cr, V) makes these compounds unique to investigate rare quantum ground states influenced by strong magnetic frustration. In this work, we investigated the thermal and magnetic properties of Cr3BO6 to find that despite very large negative Weiss temperature Θ = -160.7 K, it orders only at TN = 4.5 K and experiences a spin-flop transition at µ0H = 5 T. Density functional theory (DFT) calculations of exchange interaction parameters allow for suggesting the model of magnetic subsystem in chromium borate Cr3BO6. The results prove the decisive role of magnetic frustration on the formation of long-range order, providing therefore a basis for future study. Both experimental data and first-principles calculations point to the coexistence of chromium spin-singlets with long-range antiferromagnetic order.

One of the primary objectives of scientific research is to create state-of-the-art multiferroic (MF) materials that exhibit interconnected properties, such as piezoelectricity, magnetoelectricity, and magnetostriction, and remain functional under normal ambient temperature conditions. In this study, we employed first-principles calculations to investigate how changing pnictogen elements affect the structural, electronic, magnetic, and optical characteristics of QFeO3 (Q = Bi, P, SB). Electronic band structures reveal that BiFeO3 is a semiconductor compound; however, PFeO3 and SbFeO3 are metallic. The studied compounds are promising for spintronics, as they exhibit excellent magnetic properties. The calculated magnetic moments decreased as we replaced Bi with SB and P in BiFeO3. A red shift in the values of ε2(ω) was evident from the presented spectra as we substituted Bi with Sb and P in BiFeO3. QFeO3 (Q = Bi, P, SB) showed the maximum absorption of incident photons in the visible region. The results obtained from calculating the optical parameters suggest that these materials have a strong potential to be used in photovoltaic applications.

The electronic, optical, and magnetic properties of Nd-doped ZnO systems were calculated using the DFT/GGA + U method. According to the results, the Nd dopant causes lattice parameter expansion, negative formation energy, and bandgap narrowing, resulting in the formation of an N-type degenerate semiconductor. Overlapping of the generated impurity and Fermi levels results in a significant trap effect that prevents electron-hole recombination. The absorption spectrum demonstrates a redshift in the visible region, and the intensity increased, leading to enhanced photocatalytic performance. The Nd-doped ZnO system displays ferromagnetic, with FM coupling due to strong spd-f hybridization through magnetic exchange interaction between the Nd-4f state and O-2p, Zn-4s, and Zn-3p states. These findings imply that Nd-doped ZnO may be a promising material for DMS spintronic devices.

In this work, the effects of hydrogen (H) and oxygen (O) adsorption on the electronic and magnetic properties of graphene-like boron arsenide (BAs) monolayer are investigated using first-principles calculations. Pristine monolayer is a non-magnetic two-dimensional (2D) material, exhibiting direct gap semiconductor character with band gap of 0.75 (1.18) eV as calculated by generalized gradient approximation with Perdew-Burke-Ernzerhof (HSE06) functional. Four high-symmetry adsorption sites are considered, including on-top of B atom (TB), on-top of As atom (TAs), on-top of hollow site (TH), and on-top of bridge site (Tbridge). Using the criterion of adsorption energy, it is found thatTBandTbridgesites are favorable adsorption sites for H and O adatom, respectively. The analysis of electronic interactions indicate the charge transfer from host BAs monolayer to both adatoms. H adsorption conducts to the emergence of magnetic semiconductor nature in BAs monolayer with a total magnetic moment of 1.00 μB. Herein, the magnetism is originated mainly from H adatom and its neighbor As atoms. In contrast, the non-magnetic nature of BAs monolayer is preserved upon absorbing O atoms. In this case, the energy gap exhibits a slight reduction of 4%. Further, the effects of adatom coverage are also analyzed. The presented results suggest an effective modification of ground state electronic properties, as well as induction of new feature-rich properties to make new multifunctional 2D materials from non-magnetic BAs monolayer.

To solve the problem of the low coercivity of Nd-Fe-B-based nanowires impeding their application in magnetic storage media, highly ordered Nd-Fe-B/Fe-Co composite nanowires were fabricated in an anodic alumina template by means of the alternating electrochemical deposition method. In this paper, the effect of soft and hard magnetic phase compositing on the magnetic properties of Nd-Fe-B-based nanowires was investigated, and the coercivity improvement mechanism was demonstrated. The results show that after annealing at 600 °C for 2 h, Nd-Fe-B/Fe-Co nanowires crystallize into a multiphase structure containing a hard Nd2(Fe, Co)14B phase and soft NdB4, NdB6, Fe7Nd, and Fe7Co3 phases. It is characterized that the Nd2(Fe, Co)14B phase preferentially nucleates, followed by NdB4 + NdB6 + Fe7Nd, while Fe7Co3 has been formed in as-deposited nanowires. The existence of a Nd2(Fe, Co)14B phase with high anisotropy fields, the remanence enhancement effect produced by exchange coupling between hard-soft magnetic phases, and the pinning effect between different phases make the composite nanowires approximately exhibit single hard magnetic phase characteristics with coercivity and remanence ratio as high as 4203.25 Oe and 0.89. The results indicate that synthesizing Nd-Fe-B/Fe-Co exchange-coupled composite nanowires via alternating electrodeposition is an effective way to optimize the magnetic performance of Nd-Fe-B-based nanowires.

The green transition initiative has exposed the importance of effective recycling of Nd-Fe-B magnets for achieving sustainability and foreign independence. In this study, we considered strip-cast, hydrogenated, jet-milled Nd-Fe-B powder as a case study to explore the potential for selective chemical leaching of the Nd-rich phase, aiming to extract the Nd2Fe14B matrix phase. Diluted citric and nitric acids at concentrations of 0.01, 0.1, and 1 M were considered potential leaching mediums, and the leaching time was 15 min. Microstructural investigation, magnetic characterization, and elemental compositional analysis were performed to investigate leaching efficiency and selectivity. Based on SEM analysis, Nd/Fe ratio monitoring via ICP-MS, and the high moment/mass value at 160 emu/g for the sample leached with 1 M citric acid, 1 M citric acid proved highly selective toward the Nd-rich phase. Exposure to nitric acid resulted in a structurally damaged Nd2Fe14B matrix phase and severely diminished moment/mass value at 96.2 emu/g, thus making the nitric acid unsuitable for selective leaching. The presence of hydrogen introduced into the material via the hydrogen decrepitation process did not notably influence the leaching dynamics. The proposed leaching process based on mild organic acids is environmentally friendly and can be scaled up and adopted for reprocessing industrial scrap or end-of-life Nd-Fe-B magnets to obtain single-phase Nd-Fe-B powders that can be used for novel magnet-making.