Magnetic studies reveal near-perfect paramagnetism in the molecular semiconductor vanadyl phthalocyanine (C32H16N8VO)
| Autor: | Hans van Tol, Naresh S. Dalal, Mohindar S. Seehra, Jasleen K. Bindra, Li Pi, Zhengjun Wang |
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| Rok vydání: | 2017 |
| Předmět: |
Materials science
Magnetic moment Condensed matter physics Analytical chemistry 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Magnetic susceptibility 0104 chemical sciences Electronic Optical and Magnetic Materials law.invention Magnetic field Magnetization Paramagnetism law Antiferromagnetism Curie constant 0210 nano-technology Electron paramagnetic resonance |
| Zdroj: | Journal of Magnetism and Magnetic Materials. 422:386-390 |
| ISSN: | 0304-8853 |
| DOI: | 10.1016/j.jmmm.2016.09.018 |
| Popis: | Temperature (0.5–300 K) and magnetic field (H up to 90 kOe) dependences of the magnetization (M) of a powder sample of vanadyl phthalocyanine (VOPc) having the Phase II-triclinic structure are measured and analyzed. The data of χ = M/H vs. T measured in H = 1 kOe fit the modified Curie-Weiss (CW) law, χ = χo+C/(T−θ), with C = 6.266×10−4 emuK/gOe, θ = −0.1 K and χo = −9.3×10−7 emu/gOe. The Curie constant C yields magnetic moment μ = 1.704 μB, S = 1/2, and g = 1.967 characteristic of VO2+. The magnitude of θ = −0.1 K signifying very weak inter-ion antiferromagnetic exchange coupling is supported by the analysis of the variable frequency (9.8–336 GHz) electron paramagnetic resonance data. The isothermal data of M vs. H at ten temperatures between 0.5 K and 300 K when plotted as M vs. H/(T+0.1) collapses on to a single curve given by M = Mo tanh {gμBH/[2kB(T+0.1)]} with Mo = NgμBS = 9.48 emu/g expected for S = 1/2 system, thus signifying near perfect paramagnetism in VOPc. |
| Databáze: | OpenAIRE |
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