scholarly journals p-Wave Pairing and Colossal Magnetoresistance in Manganese Oxides

1998 ◽  
Vol 12 (13) ◽  
pp. 507-518 ◽  
Author(s):  
Yong-Jihn Kim
Keyword(s):  
Colossal Magnetoresistance ◽  
Manganese Oxides ◽  
P Wave ◽  
Ferromagnetic Phase ◽  
Sharp Drop ◽  
Wave Pairing ◽  
Magnetic Inhomogeneities ◽  
Gap Opening ◽  
Superconducting Fluctuations ◽  
Room Temperature Superconductivity

We point out that the existing experimental data of most manganese oxides show the frustratedp-wave superconducting condensation in the ferromagnetic phase in the sense that the superconducting coherence is not long enough to cover the whole system. The superconducting state is similar to the A1 state in superfluid He-3. The sharp drop of resistivity, the steep jump of specific heat, and the gap opening in tunneling are well understood in terms of the p-wave pairing. In addition, colossal magnetoresistance (CMR) is naturally explained by the superconducting fluctuations with increasing magnetic fields. The finite resistivity may be due to some magnetic inhomogeneities. This study leads to the possibility of room temperature superconductivity.

Conductivity and Isotope Effect in the Colossal Magnetoresistance

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3397-3405 ◽  
Author(s):  
Y. M. Malozovsky ◽  
J. D. Fan ◽  
D. Bagayoko
Keyword(s):  
Curie Temperature ◽  
Isotope Effect ◽  
Colossal Magnetoresistance ◽  
Manganese Oxides ◽  
Spin Diffusion ◽  
Magnetic Moments ◽  
Ferromagnetic Phase ◽  
Temperature Dependence Of Conductivity ◽  
Ferromagnetic Phase Transition ◽  
Localized Electrons

The diffusion of nearly localized electrons is considered in the presence of the spin-dependent and multiple scattering on the randomly oriented and/or distributed magnetic moments of scatterers. The spin diffusion coefficient in the case of the exchange interaction between the diffusive but nearly localized electrons is evaluated. It is shown that the electron localization leads to the vanishing of the spin diffusion and hence the ferromagnetic phase transition. The isotope effect in the Curie temperature in the case of the electron–phonon inelastic relaxation is obtained, as experimentally observed in the manganese oxides by Zhao and co-workers.11 The strong spin-polaron effect caused by the interaction of the diffusive electrons with the diffusive paramagnons significantly reduces conductivity near the Curie temperature. The temperature dependence of conductivity in the absence and presence of an external magnetic field is discussed as well.

POLARON AND SPIN-POLARON EFFECTS IN THE COLOSSAL MAGNETORESISTANCE

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3808-3814 ◽  
Author(s):  
Y. M. MALOZOVSKY ◽  
J. D. FAN
Keyword(s):  
Phase Transition ◽  
Colossal Magnetoresistance ◽  
Manganese Oxides ◽  
Spin Diffusion ◽  
Magnetic Moments ◽  
Spin Fluctuations ◽  
Ferromagnetic Phase ◽  
Spin Polaron ◽  
Ferromagnetic Phase Transition ◽  
Polaron Formation

The polaron formation due to the strong interaction of electrons with the optical phonons in a layered manganese oxides is considered. The diffusion of nearly localized polarons in the presence of the spin-dependent and multiple scattering on the randomly oriented and/or distributed magnetic moments of atoms is considered. The spin diffusion coefficient in the case of the exchange interaction between the diffusive but nearly localized polarons is evaluated. It is shown that the polaron localization leads to the vanishing of the spin diffusion and hence the ferromagnetic phase transition. The spin-polaron effect caused by the interaction of polarons with the spin fluctuations further significantly reduces conductivity near the temperature of the ferromagnetic phase transition as shown.

p-wave pairing in metals

1977 ◽  
Vol 15 (3) ◽  
pp. 1395-1398 ◽  
Author(s):  
I. F. Foulkes ◽  
B. L. Gyorffy
Keyword(s):  
P Wave ◽  
Wave Pairing

Charge - Ordered Manganeese Oxide Studied By Ω - Filter - Angular Resolved EELS

2001 ◽  
Vol 7 (S2) ◽  
pp. 1146-1147
Author(s):  
Y. Murooka ◽  
N. Tanaka ◽  
M. Hibino ◽  
K. Tsuda ◽  
M. Tanaka
Keyword(s):  
Electronic Structure ◽  
Colossal Magnetoresistance ◽  
Manganese Oxides ◽  
Charge Ordering ◽  
Nanometer Scale ◽  
Theoretical Studies ◽  
Optical Responses ◽  
Column Type ◽  
Valence Electrons ◽  
Electron Energy Loss

Despite of the intensive studies, Colossal Magnetoresistance (CMR) phenomena occurring in manganese oxides is still not fully understood. Theoretical studies based on an ordered crystal phase such as the charge-ordering (CO) phase have shown some successes in reproducing experimental evidences. Recently it was, however, shown that such a CO phase included giant clusters which were as large as 100 nm. This indicates the importance of the nanometer-scale information about the electronic structure to understand the CO. La0.5Sr1.5MnO4 is one of the oxides under intense investigations. in the CO phase, the eg valence electrons were found to be ordered at Mn sites. The optical responses of the CO clusters, however, has not been studied. in this study we have attempted to obtain such information from CO clusters in La0.5Sr1.5MnO4 by angular-resolved electron-energy-loss-spectroscopy (EELS) using an in-column type Ω-spectrometer.

SPATIAL FLUCTUATIONS OF THE ORDER PARAMETER IN A DISORDERED SUPERCONDUCTOR WITH p-WAVE PAIRING

2002 ◽  
Vol 16 (03) ◽  
pp. 453-461 ◽  
Author(s):  
GRZEGORZ LITAK
Keyword(s):  
Perturbation Method ◽  
Hubbard Model ◽  
Order Parameter ◽  
Pairing Symmetry ◽  
P Wave ◽  
Real Solution ◽  
The Real ◽  
Wave Pairing ◽  
Spatial Fluctuations ◽  
Effect Of Disorder

The effect of nonmagnetic disorder on the pairing amplitude is studied by means of a perturbation method. Using an extended one band Hubbard model with an intersite attraction we analyze various solutions of p-wave pairing symmetry and discuss their instability calculating fluctuations of order parameter. The model is applied to describe the effect of disorder in Sr2RuO4. The results shows that the real solution with line nodes can be favoured by disorder.

scholarly journals Generalized Aubry-André-Harper model with modulated hopping and p -wave pairing

2019 ◽  
Vol 100 (6) ◽  
Author(s):  
M. Yahyavi ◽  
B. Hetényi ◽  
B. Tanatar
Keyword(s):  
P Wave ◽  
Wave Pairing

PHONON-ENHANCED KONDO LATTICE MODEL IN COLOSSAL MAGNETORESISTIVE MANGANITES

2006 ◽  
Vol 20 (01) ◽  
pp. 25-29
Author(s):  
JE HUAN KOO ◽  
GUANGSUP CHO
Keyword(s):  
Lattice Model ◽  
Colossal Magnetoresistance ◽  
Manganese Oxides ◽  
Kondo Lattice ◽  
Colossal Magnetoresistive ◽  
Hole Conduction ◽  
Kondo Lattice Model ◽  
Jahn Teller ◽  
Peierls Transition

We investigate theoretically manganese oxides where the colossal magnetoresistance (CMR) is observed. Recent studies show that, if there are both an electron and a hole in the eg-band of Mn , the Jahn–Teller distortions split the band into a conduction band [Formula: see text] and a localized band [Formula: see text]. We find a Kondo lattice model with hole conduction in manganese oxides when the electron in the localized eg-band [Formula: see text] plays the role of the Kondo impurity. The Curie temperature (Tc) and the resistivity are calculated. We also calculate the antiferromagnetic temperature by a spin-Peierls transition.

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