SUPEREXCHANGE INTERACTION IN COLOSSAL MAGNETORESISTIVE MANGANITES, Tl2Mn2O7

2006 ◽  
Vol 20 (18) ◽  
pp. 1093-1097
Author(s):  
JE HUAN KOO ◽  
GUANGSUP CHO
Keyword(s):  
Curie Temperature ◽  
Manganese Oxide ◽  
Colossal Magnetoresistance ◽  
Scattering Matrix ◽  
Superexchange Interaction ◽  
Oxide Material ◽  
Colossal Magnetoresistive

We have investigated a different manganese oxide material in which the colossal magnetoresistance (CMR) is observed. As many recent evidences suggest that a superexchange interaction is dominated in the pyrochlore Tl 2 Mn 2 O 7, it is found that the superexchange interaction is a chief mechanism driving the ferromagnetism. We specially formulate the superexchange interaction to calculate the resistivity in analogy with the t-scattering matrix of the Kondo formalism. We compare our calculation for resistivity with results of experiments and obtain the Curie temperature, Tc.

ISOTOPE EFFECTS OF Mn AND O IN COLOSSAL MAGNETORESISTIVE MANGANITES

2005 ◽  
Vol 19 (30) ◽  
pp. 4427-4436
Author(s):  
JE HUAN KOO ◽  
GUANGSUP CHO
Keyword(s):  
Transition Temperature ◽  
Curie Temperature ◽  
Colossal Magnetoresistance ◽  
Manganese Oxides ◽  
Isotope Effects ◽  
Kondo Lattice ◽  
Ferromagnetic Transition ◽  
Colossal Magnetoresistive ◽  
Kondo Lattice Model ◽  
Peierls Transition

We investigate theoretically manganese oxides where the colossal magnetoresistance (CMR) is observed. We obtain the Curie temperature Tc using a Kondo lattice model for paramagetic to ferromagnetic transition. We also acquire the charge-ordered transition temperature TCO applying spin-Peierls transition. We calculate the isotope exponents of Mn ion and O ion such as αc for Tc and αCO for TCO. Calculated αc of O ion is less than 0.9 and αCO is ~-(0.1~0.9).

Electrical behavior of an octahedral layered OL-1-type manganese oxide material

Ionics ◽  
2012 ◽  
Vol 19 (2) ◽  
pp. 201-214 ◽  
Author(s):  
N. P. Arias ◽  
M. T. Dávila ◽  
O. Giraldo
Keyword(s):  
Manganese Oxide ◽  
Oxide Material ◽  
Electrical Behavior

Relation between giant volume magnetostriction and colossal magnetoresistance near the Curie temperature of Sm0.55Sr0.45MnO3

2000 ◽  
Vol 42 (8) ◽  
pp. 1494-1498 ◽  
Author(s):  
A. I. Abramovich ◽  
L. I. Koroleva ◽  
A. V. Michurin ◽  
O. Yu. Gorbenko ◽  
A. R. Kaul’
Keyword(s):  
Curie Temperature ◽  
Colossal Magnetoresistance ◽  
Volume Magnetostriction

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.

The effects of Ni and Li doping on the performance of lithium manganese oxide material for lithium secondary batteries

2002 ◽  
Vol 47 (18) ◽  
pp. 2937-2942 ◽  
Author(s):  
Ki Soo Park ◽  
Myung Hun Cho ◽  
Sang Ho Park ◽  
Kee Suk Nahm ◽  
Yang Kook Sun ◽  
...  
Keyword(s):  
Manganese Oxide ◽  
Lithium Manganese Oxide ◽  
Oxide Material ◽  
Lithium Secondary Batteries ◽  
Li Doping ◽  
Lithium Manganese

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.

Paramagnetic anomalies above the Curie temperature and colossal magnetoresistance in optimally doped manganites

2000 ◽  
Vol 62 (9) ◽  
pp. 5313-5315 ◽  
Author(s):  
S. L. Yuan ◽  
J. Q. Li ◽  
Y. Jiang ◽  
Y. P. Yang ◽  
X. Y. Zeng ◽  
...  
Keyword(s):  
Curie Temperature ◽  
Colossal Magnetoresistance ◽  
Doped Manganites
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