We have studied the structural and magnetic properties of Ni(2)MnGa(1-x)B(x) Heusler alloys with 0≤x≤0.25 using x-ray diffraction, thermal expansion, electrical resistivity, and magnetization measurements. The magnetization measurements were made within the temperature interval of 5-400 K and at applied magnetic field of 0-5 T. The samples with low B concentrations (x<0.05) were found to be of the cubic L2(1) phase at 300 K. A martensitic phase along with the cubic L2(1) phase appears for x≥0.05, and the amount of the martensitic phase was found to increase with increasing x. The critical concentration of the boron substitution (within which Heusler phases exist) was found to be around x = 0.1. The cubic cell parameter was observed to decrease with increasing x in the interval 0≤x≤0.1. The alloys were ferromagnetically ordered at 5 K and the saturation magnetization (M(S)) was found to decrease with increasing boron concentration. The Curie temperatures (T(C)) and martensitic transition temperatures (T(M)) for the alloys with 0≤x≤0.25 have been determined and a phase (T-x) diagram has been constructed. T(M) increases rapidly and T(C) decreases slowly with increasing B concentration in the interval 0≤x≤0.1. The dependence of the phase transition temperatures and magnetization on B concentration is discussed.
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http://dx.doi.org/10.1088/0953-8984/20/46/465209 | DOI Listing |
Magn Reson Med
January 2025
MRI Research Centre, Physics, University of New Brunswick, Fredericton, New Brunswick, Canada.
Purpose: Magnetic resonance elastography (MRE) provides detailed maps of tissue stiffness, helping to diagnose various health conditions, but requires the use of expensive clinical MRI scanners. Our approach utilizes compact, cost-effective portable MR sensors that offer bulk characterization of material properties in a region of interest close to the surface (within 1-2 cm). This accessible instrument could enable routine monitoring and prevention of diseases not readily evaluated with conventional tools.
View Article and Find Full Text PDFFullerenes are statically pleasant species featuring symmetric cages, which can be modified upon reduction. Here, we theoretically account for the variation of 13C-NMR patterns in C60 and C70 upon six-fold reduction and the overall variation of the enabled shielding/deshielding regions induced by π and σ electrons according to different orientations of the external field and the related anisotropy. Our results show a significant modification of the chemical shift given by the main variation of the σ33 (or δ33) shielding component under the principal axis system (PAS) of the chemical shift anisotropy (CSA) at the representative carbon nucleus.
View Article and Find Full Text PDFChemistry
January 2025
Jadavpur University, Chemistry, 188 Raja S. C. Mallick Road, 700032, Kolkata, INDIA.
Two π-radical complexes containing bisazo-aromatic-centered radical anion (1•-) were synthesized through in-situ electron transfer from metal-to-ligand using [IrI] and 2-(2-Pyridylazo)azobenzene (1) in inert hydrocarbon solvent. These are characterized as diradical [IrIII(1•-)2]+[2]+ and monoradical [IrIII(1•-)Cl2(PPh3)] 3. In contrast, a rare metal-mediated hydrolytic cleavage of the C(sp2)-N bond occurred in protic solvent resulting in quaternary radical complex [IrIII(1•-)(1')(PPh3)]+(4)+.
View Article and Find Full Text PDFDalton Trans
January 2025
School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212100, Jiangsu, China.
Five alkali metal manganese(III) fluorophosphates, KMn(POF)F (I), RbMn(POF)F (II), RbMn(POF)(PO)F (III), RbMn(POF)(PO)F (IV), and CsMn(POF)F (V), were successfully synthesized using a hydrothermal method. The monofluorophosphate anion (POF) groups work as "chemical scissors" to promote low-dimensional spin structures with the aid of alkali metal cations. I and II had an = 2 uniform chain structure formed by corner-sharing -MnOF octahedra.
View Article and Find Full Text PDFJ Mol Model
January 2025
Department of Physics, University of Malakand, Chakdara, Dir (Lower), 18800, KP, Pakistan.
Context: The structural stability, ground state magnetic order, electronic, elastic and thermoelectric properties of NdMn in the C15, C14 and C36 polytypic phases is investigated. The magnetic phase optimization and magnetic susceptibility reveal that NdMn is antiferromagnetic (AFM) in C36 phase; and paramagnetic (PM) in C14 and C15 phases respectively. The band profiles and electrical resistivity show the metallic nature in all these polytypic phases and reveal that the C36 phase possesses smaller resistivity.
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