Electronic and magnetic properties of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">FeBr</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Ropka, Z.; Michalski, Rafał; Radwański, R. J.

doi:10.1103/physrevb.63.172404

Cited by 43 publications

(41 citation statements)

References 9 publications

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“…This process is expected to result in a broad peak in T −1 1 (T ) similar to observations in precursor regions of magnetic ordering and spin freezing. The recent suggestion [20] that the reduction of n mag maybe explained by conventional crystal-field effects and spinorbit coupling of the V 4+ ions is judged as unconvincing, because in such a scenario, the peak in T −1 1 (T ) is not expected.…”

Section: Nmr At High Temperatures T > 40 Kmentioning

confidence: 99%

Unusual magnetic properties of the low-dimensional quantum magnetNa2V3O7

et al. 2005

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We report the results of low-temperature measurements of the specific heat Cp(T ), ac susceptibility χac(T ) and 23 Na nuclear magnetic resonance NMR of Na2V3O7. At liquid He temperatures Cp(T )/T exhibits broad field-dependent maxima centered at T0(H), which shift to higher temperatures upon increasing the applied magnetic field H. Below 1.5 K the ac magnetic susceptibility χac(T ) follows a Curie-Weiss law and exhibits a cusp at 0.086 mK which indicates a phase transition at very low temperatures. These results support the previous conjecture that Na2V3O7 is close to a quantum critical point (QCP) at µ0H ≈ 0 T. The entire data set, including results of measurements of the NMR spin-lattice relaxation T −1 1 (T ), reveals a complex magnetic behavior at low temperatures. We argue that it is due to a distribution of singlet-triplet energy gaps of dimerized V moments. The dimerization process evolves over a rather broad temperature range around and below 100 K. At the lowest temperatures the magnetic properties are dominated by the response of only a minor fraction of the V moments.

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Section: Nmr At High Temperatures T > 40 Kmentioning

confidence: 99%

Unusual magnetic properties of the low-dimensional quantum magnetNa2V3O7

et al. 2005

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“…It is to note that the DM interaction is a consequence of spin-orbit coupling (SOC) [9] which was, however, either neglected or not given due weightage in the above two independent calculations, rather treating V 4 þ ions as free S ¼1/2 ions in the D 3d CF [11]. However literature reviews definitely pointed out that for many 3d-compounds as MgV 2 O 5 , BaVS 3 [12], Na 2 V 3 O 7 [13], LaCoO 3 [14], NiO [15], YTiO 3 [16], FeBr 2 [17], etc. despite the weakness of the SOC, one 3d electron embedded in a solid cannot be treated as having spin-only degrees of freedom in the CF, and orbital magnetism have a significant contribution due to the quenching (or un-quenching) effect of the orbital moment of 3d-ions on the electronic and magnetic properties, namely, dc magnetic susceptibility, Curie temperature, g-values, CF splitting of the electronic states, etc.…”

Section: Introductionmentioning

confidence: 99%

“…In Section 2, we construct and diagonalize a Hamiltonian in the 9LSL z S z S basis appropriate to the 10-fold degenerate 2 D term originating from the 3d 1 electronic configuration of V-ion within the frame work of a CF theory and a mean-field (MF) approximation by adopting long-range dipolar and anisotropic exchange interactions [19] among V-ions situated on the tetrahedral sublattice. The Hamiltonian thus somehow resembles the hybridization of Quantum Atomistic Solid-State Theory (QUASST) developed by Radwanski et al [12][13][14][15][16][17] and the CF þMF model proposed by Malkin et al [19] Exact relations between the bulk and single-ion susceptibility were used to simulate the experimental susceptibility of these two pyrochlores. In Section 3, we analyze our calculated results, and finally in Section 4, a discussion followed by conclusions is given.…”

Section: Introductionmentioning

confidence: 99%

Crystal-field, exchange interactions and magnetism in pyrochlore ferromagnet R2V2O7 (R3+=Y, Lu)

Biswas

Jana

2013

Journal of Magnetism and Magnetic Materials

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“…The semicore states are treated in a separate energy window. The k-space integration is done with 30 k-points in irreducible part of Brillouin Zone(IBZ)(144 k-points in full Brillouin Zone(FBZ)) us- a Reference [9] b Reference [8] ing the tetrahedron method. 17 We have also carried out calculations with larger set of k-points (43 points in IBZ and 320 points in FBZ), but the total energies are found to be converged within 1 meV and magnetic moments change within 0.01 µ B .…”

mentioning

confidence: 99%

Large orbital magnetic moment and Coulomb correlation effects inFeBr2

2002

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We have performed an all-electron fully relativistic density functional calculation to study the magnetic properties of FeBr2. We show for the first time that the correlation effect enhances the contribution from orbital degrees of freedom of d electrons to the total magnetic moment on Fe 2+ as opposed to common notion of nearly total quenching of the orbital moment on Fe 2+ site. The insulating nature of the system is correctly predicted when the Hubbard parameter U is included. Energy bands around the gap are very narrow in width and originate from the localized Fe-3d orbitals, which indicates that FeBr2 is a typical example of the Mott insulator.PACS numbers: 74.25. Ha, 71.27.+a, FeX 2 (X= Cl, Br, I) are well known model systems for the study of antiferromagnetism. 1 They show unusual metamagnetic behavior wherein they undergo a phase transition from the antiferromagnetic to a saturated paramagnetic phase as a function of external magnetic field and temperature. FeBr 2 has a layered structure, where the ferromagnetic Fe layers are widely separated by non-magnetic halogen layers producing a quite weak interlayer antiferromagnetic interactions (T N = 14.2 K). The long range antiferromagnetic ordering can be overcome by applying an external magnetic field (∼ 30 kOe) parallel to the c-axis. 2 As a result, many theoretical 3 and experimental 4,5 works on FeBr 2 have been concentrated on probing the axial magnetic phase diagram, to predict and understand anomalies near the antiferromagnetic to the paramagnetic phase boundary.In addition, the electronic structures of transition metal dihalide system are of interest because they show various types of interesting behavior due to the strong correlation effect in the transition metal ion. 6 For example, they behave as a Mott insulator or charge transfer type insulator depending upon the relative size of charge transfer energy ∆ and the intra-orbital correlation energy U of the d-electrons.Although large amount of work is done to understand the anomalies in the phase diagram and the correlation effects, surprisingly no electronic structure is known from the first principles calculation. In this report, we study the electronic and magnetic properties of one of these systems (FeBr 2 ) by combining a first principles method and the Hubbard on-site correlation term.Orbital magnetic moment plays a crucial role in determining many important effects in magnetic materials such as magnetic crystalline anisotropy, non-collinear magnetism, magneto-optical Kerr effect etc.. 7 It is a well known fact that crystal field interaction quenches the orbital magnetic moment in systems containing 3d-transition metal. Accordingly, it is assumed that because of strong crystalline field on Fe 2+ ions from the surrounding Br − , the orbital moment will also get quenched in FeBr 2 . 8 Ropka, Michalski, and Radwanski 9 showed that the orbital moment is not quenched fully by the crystal field through their quasi-atomic calculation. Ropka et al. ascribed the origin of the large orbital moment to spi...

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Electronic and magnetic properties ofFeBr2

Cited by 43 publications

References 9 publications

Unusual magnetic properties of the low-dimensional quantum magnetNa2V3O7

Unusual magnetic properties of the low-dimensional quantum magnetNa2V3O7

Crystal-field, exchange interactions and magnetism in pyrochlore ferromagnet R2V2O7 (R3+=Y, Lu)

Large orbital magnetic moment and Coulomb correlation effects inFeBr2

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