Antiferromagnetism and onset of Superconductivity in Lanthanum Nickelates

1989 ◽  
Vol 156 ◽  
Author(s):  
J. Spałek ◽  
Z. Kakol ◽  
J. M. Honig
Keyword(s):  
Phase Separation ◽  
Magnetic Moment ◽  
Ground State ◽  
Phase 1 ◽  
Structural Phase ◽  
Resistivity Measurements ◽  
Minority Phase

ABSTRACTMagnetic moment and resistivity measurements are summarized for the La2−xSrxNiO4 system. They show that the system undergoes a structural phase separation below 70 K. The majority of the sample is antiferromagnetic (AF) below 650 K (for x = 0) or 20 K (for x = 0) or 20 K (for x ≃ 0.2 while the minority phase (≤1% at 4.2 K) is superconducting (SC). An analysis of the results leads to the conclusion that SC and AF coexist in the minority part of the sample; the pairing takes place between 2p holes which propagate through a lattice containing localized 3d moments which, in the ground state, are ordered antiferromagnetically.

scholarly journals Investigation of a Structural Phase Transition and Magnetic Structure of Na2BaFe(VO4)2: A Triangular Magnetic Lattice with a Ferromagnetic Ground State

2017 ◽  
Vol 56 (24) ◽  
pp. 14842-14849 ◽  
Author(s):  
Liurukara D. Sanjeewa ◽  
Vasile O. Garlea ◽  
Michael A. McGuire ◽  
Matthias Frontzek ◽  
Colin D. McMillen ◽  
...  
Keyword(s):  
Phase Transition ◽  
Magnetic Structure ◽  
Structural Phase Transition ◽  
Ground State ◽  
Structural Phase ◽  
Ferromagnetic Ground State

Magnetic moment and electric quadrupole moment of the N ground state

1999 ◽  
Vol 451 (1-2) ◽  
pp. 11-18 ◽  
Author(s):  
H. Ogawa ◽  
K. Asahi ◽  
K. Sakai ◽  
A. Yoshimi ◽  
M. Tsuda ◽  
...  
Keyword(s):  
Quadrupole Moment ◽  
Magnetic Moment ◽  
Ground State ◽  
Electric Quadrupole ◽  
Electric Quadrupole Moment

Evolution of Ce-Valence in Ce-Rh-Si Compounds: Intermediate Valence in CeRh6Si4

2016 ◽  
Vol 257 ◽  
pp. 199-202
Author(s):  
Thomas Gruner ◽  
Christoph Geibel
Keyword(s):  
Ground State ◽  
Low Temperatures ◽  
Ternary Phase ◽  
Ternary Phase Diagram ◽  
Intermediate Valence ◽  
Characteristic Energy ◽  
X Ray ◽  
Resistivity Measurements ◽  
Intermediate Valent ◽  
X Ray Absorption

We synthesized polycrystalline samples of CeRh6Si4 and investigated its physical properties by means of magnetic susceptibility, specific heat and electrical resistivity measurements as well as LIII X-ray absorption spectroscopy. All results evidence an intermediate-valent (IV) Ce state with a valence close to 3.2 and a characteristic energy of about 300 K. Accordingly, we observe a Fermi liquid ground state at low temperatures with a slightly enhanced Sommerfeld coefficient γ = 28 mJ/molK2. Using presently available data on different compounds, we analyze the evolution of the Ce valence in the Ce-Rh-Si ternary phase diagram. The expected correlation with the distance to nearest Ce-ligands can be discerned. Thus, the evolution from a trivalent Ce3+ state in CeRh3Si2 to an IV state in CeRh6Si4 is related to a shortening of both the Ce-Rh and Ce-Si bonds in the first coordination sphere of Ce.

scholarly journals Magnetism and phase separation in the ground state of the Hubbard model

2002 ◽  
Vol 27 (4) ◽  
pp. 473-481 ◽  
Author(s):  
R. Zitzler ◽  
Th. Pruschke ◽  
R. Bulla
Keyword(s):  
Phase Separation ◽  
Hubbard Model ◽  
Ground State

Detailed analysis of magnetism in Ru monolayers

2004 ◽  
Vol 82 (9) ◽  
pp. 717-729 ◽  
Author(s):  
L M García-Cruz ◽  
A Rubio-Ponce ◽  
A E García ◽  
R Baquero
Keyword(s):  
Density Of States ◽  
Magnetic Moment ◽  
Ground State ◽  
Electronic States ◽  
Magnetic Behavior ◽  
Nearest Neighbors ◽  
Lattice Parameter ◽  
Magnetic Activity ◽  
First Impression ◽  
The One

We study the magnetic behavior of a 4d transition-metal Ru monolayer (ML) on different substrates and orientations. In the ground state, an ideal Ru-ML is expected to be ferromagnetic on Ag(001) and Au(001) with a magnetic moment, µ, around 1.7 µB (Bohr magnetons) in both cases. On Cu(001), a Ru-ML is not magnetic. In this paper, we study the magnetic behavior of a Ru-ML at other orientations, i.e., (110) and (111), and analyze the phenomenon as a whole. We find magnetism on Au(111), and Ag(111) (µ ≈ 1 µB for both) but no magnetic activity on a Cu substrate in any orientation. This gives the first impression that the lattice parameter of the substrate is the one that governs the switching on of magnetism in the Ru-ML. But then, we find that on both Ag(110) and Au(110), an ideal Ru-ML is not magnetic. For that reason, we have tried to find another geometric parameter that would correlate better with the magnetic moment. We find that neither the total number of first nearest neighbors for each orientation, nor the number of them on the ML, or the number of them in the substrate, or the area per atom on the ML, correlate. We find a correlation with a parameter, Ω0, that represents the volume per atom in the monolayer–substrate interface region. But this parameter seems to have the wrong trend according to intuition. Further analysis shows that the details of the interaction are important, and that the physics underlying the switching on of magnetism in a Ru-ML on noble metal substrates, is determined by an intraband transfer of d-electronic states, from lower and higher energies to the Fermi level, that enhances the density of states at that energy, in an important way. This depends on specificities of the interaction between the ML and the substrate that are hardly taken into account by a single parameter that is merely geometric. PACS Nos.: 75.10–b, 75.30–m, 75.70.Ak, 73.20.At

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