High-Field Magnetization Studies of Two-Dimensional Copper Antiferromagnets

Turnbull, Mark M.; Albrecht, A. S.; Jameson, Geoffrey B.

doi:10.1080/10587259908028869

Cited by 24 publications

(9 citation statements)

References 17 publications

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“…Pulsed magnetic field measurements Figure 3 shows the magnetization of the four compounds measured in pulsed magnetic fields at temperatures close to 0.60 K. Pulsed-field data have been previously reported for 1, 2 [11] and 4 [46]. Apart from a low-field hump seen in 3, possibly due to a small concentration of paramagnetic impurities, the form of the lowtemperature magnetization in all cases is very similar: a gradual concave rise to the saturation field H c .…”

Section: Intralayer Magnetic Exchange Energiesmentioning

confidence: 82%

Control of the third dimension in copper-based square-lattice antiferromagnets

et al. 2016

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Using a mixed-ligand synthetic scheme, we create a family of quasi-two-dimensional antiferromagnets, namely, [Cu(HF2)(pyz)2]ClO4 [pyz = pyrazine], [CuL2(pyz)2](ClO4)2 [L = pyO = pyridine-N-oxide and 4-phpyO = 4-phenylpyridine-N-oxide. These materials are shown to possess equivalent two-dimensional [Cu(pyz)2] 2+ nearly square layers, but exhibit interlayer spacings that vary from 6.5713Å to 16.777Å, as dictated by the axial ligands. We present the structural and magnetic properties of this family as determined via x-ray diffraction, electron-spin resonance, pulsed-and quasistatic-field magnetometry and muon-spin rotation, and compare them to those of the prototypical two-dimensional magnetic polymer Cu(pyz)2(ClO4)2. We find that, within the limits of the experimental error, the two-dimensional, intralayer exchange coupling in our family of materials remains largely unaffected by the axial ligand substitution, while the observed magnetic ordering temperature (1.91 K for the material with the HF2 axial ligand, 1.70 K for the pyO and 1.63 K for the 4-phpyO) decreases slowly with increasing layer separation. Despite the structural motifs common to this family and Cu(pyz)2(ClO4)2, the latter has significantly stronger two-dimensional exchange interactions and hence a higher ordering temperature. We discuss these results, as well as the mechanisms that might drive the long-range order in these materials, in terms of departures from the ideal S = 1/2 two-dimensional square-lattice Heisenberg antiferromagnet. In particular, we find that both spin exchange anisotropy in the intralayer interaction and interlayer couplings (exchange, dipolar, or both) are needed to account for the observed ordering temperatures, with the intralayer anisotropy becoming more important as the layers are pulled further apart.

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Section: Intralayer Magnetic Exchange Energiesmentioning

confidence: 82%

Control of the third dimension in copper-based square-lattice antiferromagnets

et al. 2016

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“…The value of αJ = 8.2 K is identified as being mediated by the pyrazine bridges. This makes sense when we look back to a number of coordination compounds consisting of 2D layers of pyrazine that have been previously studied [23][24][25] Now that the simulations have been combined into a model for susceptibility data for general α, it is prudent to refit the Cu(pz)Cl 2 data to check for consistency. Cu(pz)Cl 2 was fit to the 2D AF/af rectangular model [Eq.…”

Section: Cu(pz)clmentioning

confidence: 99%

Two-dimensional spin-12rectangular Heisenberg antiferromagnets: Simulation and experiment

et al. 2011

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We have simulated and analyzed the susceptibility of a series of two-dimensional (2D) spin-1 2 rectangular Heisenberg antiferromagnetic (as well as mixed exchange antiferromagnetic/ferromagnetic) lattices as a function of J,J and temperature, where J is the dominant magnetic exchange interaction and J , the orthogonal interaction, is related to J by J = αJ , where α can vary from 0 to 1. Previous studies of the compounds pyrazineformatocopper(II) nitrate [Cu(pz)(HCO 2 )](NO 3 ), catena-2-aminopyrimidinedichlorocopper(II) [Cu(2-apm)Cl 2 ], and catena-pyrazinediazidocopper(II) [Cu(pz)(N 3 ) 2 ] indicated that these systems had 2D magnetic spin-spin interactions. However, there were no 2D models that could capture the behavior of any measurable bulk properties of the compounds. The previous authors fit the susceptibility data of the respective compounds to a 1D antiferromagnetic chain with a mean-field correction, or did not fit the data at all. We use the simulations to create this fit function in order to test the 2D model proposed for these spin systems.

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“…Perhaps the difficulty in synthesis and the thermal and photochemical instability of tetz itself have contributed to the relative scarcity of well-defined coordination compounds of tetz and its derivatives. We have long been interested in the synthesis of new low-dimensional magnetic systems and have prepared and studied a number of linear chain [12][13][14] and square layer systems [15,16]. We report here the synthesis, structure, thermal properties and powder magnetic susceptibility of bis(hexafluoroacetylacetonato)tetrazinecopper(II), Cu(hfac) 2 (tetz) (1).…”

Section: Synthesis Crystal Structure and Properties Of Bis(hexafluormentioning

confidence: 99%

Synthesis, crystal structure and properties of bis(hexafluoroacetylacetonato)tetrazinecopper(II)

Landee

Twamley

2006

Journal of Coordination Chemistry

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A new complex bis(hexafluoroacetylacetonato)tetrazinecopper(II), Cu(hfac) 2 (tetz) (1), has been prepared by reaction of Cu(hfac) 2 Á xH 2 O and 1,2,4,5-tetrazine in CH 2 Cl 2 . Orange crystals suitable for X-ray diffraction analysis of 1 were obtained by slow evaporation at room temperature. Complex 1 crystallizes in the triclinic space group P 1, with a ¼ 11.4825 (7), b ¼ 13.4950(8), c ¼ 13.8328(8) Å , ¼ 104.990(1), ¼ 111.888(1), ¼ 94.245(1) , V ¼ 1886.23(19) Å 3 , R 1 ¼ 0.0507 based on 6814 independent reflections. The complex is unstable at room temperature and decomposes with loss of the tetz ligand. Differential scanning calorimetry (DSC) and magnetic properties are reported.

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High-Field Magnetization Studies of Two-Dimensional Copper Antiferromagnets

Cited by 24 publications

References 17 publications

Control of the third dimension in copper-based square-lattice antiferromagnets

Control of the third dimension in copper-based square-lattice antiferromagnets

Two-dimensional spin-12rectangular Heisenberg antiferromagnets: Simulation and experiment

Synthesis, crystal structure and properties of bis(hexafluoroacetylacetonato)tetrazinecopper(II)

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