Specific heat and orbital moment of CoO from first-principles atomistic calculations (2009)
We have for the first time calculated low-energy electronic structure both in paramagnetic and magnetic state as well as zero-temperature properties and thermodynamics. We consistently described...
Magnetic properties and the electronic structure of LiCoO_2 (2006)
We have described properties of LiCoO_2 within the Quantum Atomistic Solid State (QUASST) theory taking into account very strong electron correlations, predominantly of the intra-atomic origin,...
NiO - from first principles (2006)
We have calculated from first-principles the octupolar interactions of the Ni2+ ion in NiO, which gives the theoretical basis for the ionic description of properties of NiO with fully localized...
In contrary to authors of Phys. Rev. Lett. 93, 126406 (2004) claiming "the band picture to be a reasonable starting point for the description of the electronic structure of NiO, much better than the...
The Jahn-Teller theorem for 3d ions and their compounds (2006)
In contrary to customarily consideration of the Jahn-Teller theorem for 3d-ion compounds in the orbital space only we point out that it has to be considered in the spin-orbital space. It is despite...
Comment on a Phys. Rev. Lett. paper: the origin of the excited state in LaCoO3 (2006)
In contrary to a claim of the recent Phys. Rev. Lett. 96 (2006) 027201 paper we maintain that the first excited state in LaCoO3 is the high-spin (HS) state (a lowest quasi-triplet from the octahedral...
LaCoO3 - from first principles (2006)
We have performed calculations of the electronic structure of LaCoO3 from first principles, assuming the atomistic construction of matter and the electrostatic origin of the crystal-field splitting....
Crystal field, spin-orbit coupling and magnetism in a ferromagnet YTiO3 (2006)
Magnetic properties of stechiometric YTiO3 has been calculated within the single-ion-based paradigm taking into account the low-symmetry crystal field and the intra-atomic spin-orbit coupling of the...
We claim that any approach neglecting the spin-orbit coupling and the orbital magnetism is not physically adequate for 3d oxides, including NiO, and that in reaching "excellent agreement" in a Phys....
We argue that the electronic structure considered in a Phys. Rev. Lett. paper 94 (2005) 146402 of the Co3+ ion in the CoO6 octahedron of NaxCoO2 is completely wrong. The presented Fig. 1 is redrawn...
On the crystal field in the modern solid-state theory (2005)
We point out the high physical correctness of the use and the concept of the crystal-field approach, even if is used to metallic magnetic materials of transition-metal 3d/4f/5f compounds. We discuss...
The atomic-start description of NiO (2005)
We have calculated magnetic properties and the electronic structure of NiO both in the paramagnetic and in magnetically-ordered state as well as zero-temperature properties and thermodynamics within...
The low-energy electronic structure and the orbital magnetism in NiO (2004)
The orbital and spin moment of the Ni2+ ion in NiO has been calculated within the quasi-atomic approach. The orbital moment of 0.46 mu_B amounts at 0 K, in the magnetically-ordered state, to about...
Are there crystal field levels in UPd2Al3? We answer, THERE ARE (2004)
We claim that crystal field (CEF) levels exist in UPd2Al3 in contrary to a recent claim of Hiess et al. (cond-mat/0411041) and Bernhoeft et al. (cond-mat/0411042), that there is no experimental...
Quadrupolar interactions in heavy fermion metal YbRh2Si2 (2004)
We describe the experimentally revealed by Sichelschmidt et al, Phys. Rev. Lett. 91 (2003) 156401, g tensor, g_perpendicular=3.561 and g_parallel=0.17, at 5 K by means of crystal field interactions...
Violation of the Curie law in Na2V3O7 as the crystal-field and spin-orbit coupling effect (2004)
We have shown that the observed drastic violation of the Curie-Weiss law in Na2V3O7, reported in Phys. Rev. Lett. 90 (2003) 167202, is caused by conventional crystal-field interactions and the...
We argue that the 3A2 state considered by Oles in Phys. Stat. Sol. (b) 236 (2003) 281 for the d2 system occurring in the V3+ ion in V2O3 and LaVO3 as well as in Ti2+ ion in TiO and in many other...
Strongly correlated crystal-field approach to Mott insulator LaCoO3 (2004)
Our success in description of recent electron-spin-resonance results on Mott insulator LaCoO3, Phys. Rev. B 67 (2003) 172401, lies in taking into account strong electron correlations among d...
Magnetism and fine electronic structure of UPd2Al3 and NpPd2Al3 (2004)
We claim the existence of the f3 (U3+) configuration in UPd2Al3. It is in agreement with inelastic-neutron-scattering (INS) excitations and is consistent with the trivalent neptunium configuration in...
We have developed the crystal-field approach with strong electron correlations, extended to the Quantum Atomistic Solid-State theory (QUASST), as a physically relevant theoretical model for the...
Ground state, electronic structure and magnetism of LaMnO3 (2004)
We have calculated the discrete low-energy electronic structure in LaMnO3 originating from the atomic-like states of the strongly correlated 3d4 electronic system occurring in the Mn3+ ion. We take...
We provide the microscopic explanation for the localized f state observed in a heavy fermion metal YbRh2Si2 by Prof. F. Steglich's group, reported recently in Phys. Rev. Lett. 91 (2003) 156401, as...
Crystal-field ground state for the localized f state in heavy fermion metal YbRh2Si2 (2003)
We fully support the interpretation of Prof. F. Steglich, reported recently in Phys. Rev. Lett. 91 (2003)156401, that the observed \textit{below} Kondo temperature, Electron Spin Resonance (ESR) in a...
Comment on "Low-dimensional spin S=1/2 system at the quantum critical limit: Na2V3O7" (2003)
We contest the interpretation by Gavilano et al. (Phys.Rev.Lett. 90 (2003) 167202) of violation of the Curie law behavior of the paramagnetic susceptibility at low temperatures by means of the...
Orbital and spin moment in CoO (2003)
The orbital and spin moment of the Co2+ ion in CoO has been calculated within the quasi-atomic approach with taking into account the intra-atomic spin-orbit coupling and crystal field interactions....
Spin-orbit origin of large reduction of the effective moment in Na2V3O7* (2003)
We have shown that the observed large reduction of the effective moment and the drastic violation of the Curie-Weiss law in Na2V3O7 (Phys. Rev. Lett. 90 (2003) 167202) is caused by conventional...
A novel approach to the crystal-field theory - the orbital magnetism in 3d-ion compounds (2003)
We point out that the orbital magnetism has to be taken into account in the description of real 3d-ion compounds. According to the developed by us the Quantum-Atomistic Solid-State (QUASST) theory in...
To the origin of large reduction of the effective moment in Na2V3O7 (2003)
We have shown that the observed large reduction of the effective moment in Na2V3O7 may be caused by conventional crystal-field interactions and the intra-atomic spin-orbit coupling of the V4+ ion....
Orbital moment in CoO and in NiO (2003)
The total, orbital and spin moment of the Co2+ ion in CoO has been calculated within the quasi-atomic approach with taking into account strong correlations, crystal-field interactions and the...
Spin vs charge excitations in heavy-fermion compounds* (2003)
It is pointed out that the answer on the question about the role played by spin and charge excitations will help to solve the physical origin of the heavy- fermion phenomena. Our answer is that...
Electronic structure of the V3+ ion in V2O3 (2003)
We have attributed magnetism and electronic structure of V2O3 to the V3+ ions. We claim that the V3+ ion in V2O3 should be considered as described by the quantum numbers S=1 and L=3. Such quantum...
The 5D term origin of the excited triplet in LaCoO3 (2003)
We provide the proof for the 5D term origin of an excited triplet observed in the recent electron-spin-resonance (ESR) experiments by Noguchi et al. (Phys. Rev. B 66, 094404 (2002)). We have...
The orbital moment in CoO (2002)
The orbital and spin moment of the Co2+ ion in CoO has been calculated within the quasi-atomic approach with taking into account the intra-atomic spin-orbit coupling. The orbital moment of 1.38...
The 3d-electron states in FeBr2 (2002)
The fundamental controversy about the electronic structure for 3d-electron states in FeBr2 is discussed. We advocate for the localized electron atomic-like many-electron crystal-field approach that...
The 3d-electron states in LaMnO3* (2002)
Three fundamentally different electronic structures for 3d electron states in LaMnO3, discussed in the current literature, have been presented. We are in favour of the localized electron atomic-like...
Influence of spin-orbit interactions on the cubic crystal-field states of the d4 system* (2002)
It has been shown that for the highly-correlated d4 electronic system the spin-orbit interactions produce, even in case of the cubic crystal-field interactions, a singlet ground state. Its magnetic...
By this Comment we would like to point out that the authors of Ref. 1 have ignored the orbital magnetism that makes the theory irrelevant to the real systems like NiO.It causes that the calculated...
Comment on "Orbitally degenerate spin-1 model for insulating V2O3" (2000)
We criticize the model proposed by Mila et al. (Phys.Rev.Lett. 85 (2000) 1714) for the description of the V3+ ion in V2O3 by pointing out that it is completely artificial because the condition about...
The 3d-electron states in LaCoO3 (2000)
Three fundamentally different electronic structures for 3d electron states in LaCoO3, discussed in the current literature, have been presented. We are in favour of the localized electron atomic- like...
In the commented Letter Vogt et al. (Phys.Rev.Lett. 84 (2000) 2969) claim the existence of a spin-state transition in YBaCo2O5. We think that this claim about the change from the low spin to high...
Loss of the magnetism in FeS (2000)
It is argued that the formation of the non-magnetic state of FeS in external pressures above 6.5 GPa is in agreement with the prediction of the quantum atomistic solid-state theory, an extension of...
By this Comment we would like to point out [2] that, though such consideration can be quite sophisticated, the consideration of a spin-pseudo-spin Hamiltonian has nothing in common with the reality....
Quantum Numbers of the V3+ Ion in V2o3 (2000)
It is argued that the V3+ ion in V2O3 should be considered as described by quantum numbers S=1 and L=3. It results from Hund's rules and means that the two d electrons form the highly- correlated...
Almost Non-Magnetic Ground State of the V4+ Ion: The case of BaVS3 (2000)
We have shown that the V4+ ion with 1 d electron can have almost non-magnetic ground state under the action of the octahedral crystal field in the presence of the spin-orbit coupling and off-cubic...
Quantum Atomistic Solid-State Theory (2000)
Postulates of the quantum atomistic solid-state theory (QUASST) have been presented. QUASST is an extension of the crystal-field theory and is applicable to compounds containing open-shell 3d, 4f and...
Large Orbital Magnetic Moment in Feo, Fes and Febr2 (2000)
Magnetic moment of the Fe2+ ion in FeO, FeS and FeBr2 has been calculated within the quantum atomistic solid-state theory to substantially exceed a value of 4 muB in the magnetically-ordered state at...
Large Orbital Magnetic Moment in Febr2 (2000)
Ropka, Z., Michalski, R., Radwanski, R. J.
Magnetic moment of the Fe2+ ion in FeBr2 has been calculated to be 4.32 mB in the magnetically-ordered state at 0 K. It is composed from the spin moment of 3.52 mB and the orbital moment of +0.80 mB....
Local off-cubic distortion the cause for the low- and high-spin states of the Co3+ ion (2000)
It is pointed out that it is the local symmetry that determines the realization of the low- and high-spin state of the Co3+ ion. We can rigorously prove it treating the Co3+ ion as the...
The Jahn-Teller theorem for the 3d magnetic ions (2000)
We argue that the Jahn-Teller theorem, if applied to 3d-ion compounds, has to be considered in the orbital+spin space. It is despite of the weakness of the intraatomic spin-orbit coupling.
Jahn-Teller-effect formation of the non-magnetic ground state for the d8 system (2000)
It is shown that the d8 electron system occurring in the Ni2+ ion can have the non-magnetic ground state in the atomic scale formed by the Jahn-Teller effect. The tetragonal/trigonal off-cubic...
The preservation of the individuality of 3d atoms in a solid (2000)
On basis of analysis of experimental results for more than 200 compounds with 3d and 4f elements we conjecture that atoms with unfilled 3d and 4f shells preserve much of their atomic properties,...
Electronic and Magnetic Properties of Febr2 (2000)
Ropka, Z., Michalski, R., Radwanski, R. J.
Electronic and magnetic (e-m) properties of FeBr2 have been surprisingly well described as originating from the Fe2+ ions and their fine electronic structure. The fine electronic structure have been...
The existence of the fine electronic structure in LaCoO3 (2000)
We argue that in LaCoO3 exists the fine electronic structure associated with the atomic-like states of the Co3+ ions and caused by the crystal-field and intra-atomic spin-orbit interactions. This...
The orbital and spin moment of the Ni2+ ion in NiO has been calculated at 0 K to be 0.54mB and 1.99 mB respectively. Such large orbital moment, more than 20% of the total moment of 2.53 mB, proves...
Crystal-field interactions in PrRu2Si2 (2000)
Michalski, R., Ropka, Z., Radwanski, R. J.
Ferromagnetic compound PrRu2Si2 exhibits a giant magnetocrystalline anisotropy of about 400 T. Its ordered moment below Tc=14K reaches 2.7 mB and is parallel to [0 0 1] crystalline direction. We have...
The orbital moment in NiO (2000)
Radwanski, R. J., Ropka, Z., Michalski, R.
The orbital and spin moment of the Ni2+ ion in NiO has been calculated within the quasi-atomic approach. The orbital moment of 0.54 mB amounts at 0 K, in the magnetically-ordered state, to more than...
The understanding of magnetic and electronic properties of rare-earth intermetallics is summarized. The properties of NdNi5 or ErNi5 are understood by considering a few electronic subsystems like the...
Relativistic effects in the electronic structure for the 3d paramagnetic ions (1999)
It has been shown that relativistic spin-orbit effects have enormous influence on the electronic structure of the correlated electron systems 3dn. The s-o coupling produces the fine electronic...
Anomalous temperature dependences of the susceptibility for the one-3d- electron cation (1999)
We have studied properties of the one-3d-electron cation (Ti 3+, V 4+ ions) under the action of the low-symmetry crystal field in the presence of the spin- orbit coupling. Very anomalous temperature...
The formation of a non-magnetic state for the d6 electronic system (1999)
It has been shown that the crystal-field interactions can produce a non- magnetic singlet ground state for the highly-correlated d6 system situated in the quasi-octahedral crystal field (CEF)...
In contrary to widely spread view about the substantial delocalization of f electrons in heavy- fermion (h-f) compounds it is argued that h-f phenomena can be understood with localized f electrons....
Specific Heats of R2Zn17 Intermetallic Compounds. (1998)
Marquina, C., Kim-Ngan, N. H., Bakker, K., Radwanski, R. J., Jacobs, T. H.
This paper concerned metals in some important way and contained information about, utilized, or discussed these subjects: basic topics: experimental materials and material types: dy2zn17, er2zn17,...
High-field magnetisation studies of NdNi5 (1996)
Kim-Ngan, N.H., Radwanski, R.J., Kayzel, F.E., Franse, J.J.M.
High-field magnetization and specific heat of TmNi5 (1996)
Kayzel, F.E., Franse, J.J.M., Colpa, J.H.P., Kim-Ngan, N.H., Tai, L.T., Radwanski, R.J., ...