Colossal magnetoresistance in doped manganites: A consequence of percolation and phase separation

2001 ◽  
Vol 79 (4) ◽  
pp. 506-508 ◽  
Author(s):  
A. K. Pradhan ◽  
Y. Feng ◽  
B. K. Roul ◽  
D. R. Sahu
Keyword(s):  
Phase Separation ◽  
Colossal Magnetoresistance ◽  
Doped Manganites

scholarly journals Probing Phase Separation and Local Lattice Distortions in Cuprates by Raman Spectroscopy

2019 ◽  
Vol 4 (4) ◽  
pp. 87
Author(s):  
Liarokapis
Keyword(s):  
Raman Spectroscopy ◽  
Phase Separation ◽  
High Temperature ◽  
Colossal Magnetoresistance ◽  
High Temperature Superconductors ◽  
Relaxor Ferroelectrics ◽  
Order Parameters ◽  
Characteristic Family ◽  
Local Lattice ◽  
Lattice Distortions

It is generally accepted that high temperature superconductors emerge when extra carriers are introduced in the parent state, which looks like a Mott insulator. Competition of the order parameters drives the system into a poorly defined pseudogap state before acquiring the normal Fermi liquid behavior with further doping. Within the low doping level, the system has the tendency for mesoscopic phase separation, which seems to be a general characteristic in all high Tc compounds, but also in the materials of colossal magnetoresistance or the relaxor ferroelectrics. In all these systems, metastable phases can be created by tuning physical variables, such as doping or pressure, and the competing order parameters can drive the compound to various states. Structural instabilities are expected at critical points and Raman spectroscopy is ideal for detecting them, since it is a very sensitive technique for detecting small lattice modifications and instabilities. In this article, phase separation and lattice distortions are examined on the most characteristic family of high temperature superconductors, the cuprates. The effect of doping or atomic substitutions on cuprates is examined concerning the induced phase separation and hydrostatic pressure for activating small local lattice distortions at the edge of lattice instability.

scholarly journals Theory of Insulator Metal Transition and Colossal Magnetoresistance in Doped Manganites

2004 ◽  
Vol 92 (15) ◽  
Author(s):  
T. V. Ramakrishnan ◽  
H. R. Krishnamurthy ◽  
S. R. Hassan ◽  
G. Venketeswara Pai
Keyword(s):  
Colossal Magnetoresistance ◽  
Insulator Metal Transition ◽  
Doped Manganites

Phase Separation and Destabilization of the Charge-Ordered State in Cr-Doped Manganites

2001 ◽  
Vol 70 (1) ◽  
pp. 267-271 ◽  
Author(s):  
Ryuichi Shoji ◽  
Shigeo Mori ◽  
Naoki Yamamoto ◽  
Akihiko Machida ◽  
Yutaka Moritomo ◽  
...  
Keyword(s):  
Phase Separation ◽  
Doped Manganites ◽  
Ordered State

scholarly journals Origin of colossal magnetoresistance in LaMnO3 manganite

2015 ◽  
Vol 112 (35) ◽  
pp. 10869-10872 ◽  
Author(s):  
Maria Baldini ◽  
Takaki Muramatsu ◽  
Mohammad Sherafati ◽  
Ho-kwang Mao ◽  
Lorenzo Malavasi ◽  
...  
Keyword(s):  
Phase Separation ◽  
Percolation Threshold ◽  
Memory Effect ◽  
Percolation Theory ◽  
Colossal Magnetoresistance ◽  
Magnetic Clusters ◽  
Model Hamiltonian ◽  
Large Memory ◽  
Crucial Ingredient

Phase separation is a crucial ingredient of the physics of manganites; however, the role of mixed phases in the development of the colossal magnetoresistance (CMR) phenomenon still needs to be clarified. We report the realization of CMR in a single-valent LaMnO3 manganite. We found that the insulator-to-metal transition at 32 GPa is well described using the percolation theory. Pressure induces phase separation, and the CMR takes place at the percolation threshold. A large memory effect is observed together with the CMR, suggesting the presence of magnetic clusters. The phase separation scenario is well reproduced, solving a model Hamiltonian. Our results demonstrate in a clean way that phase separation is at the origin of CMR in LaMnO3.

Theory of ferromagnetism and colossal magnetoresistance in doped manganites

1999 ◽  
Vol 85 (8) ◽  
pp. 4349-4351 ◽  
Author(s):  
A. S. Alexandrov ◽  
A. M. Bratkovsky
Keyword(s):  
Colossal Magnetoresistance ◽  
Doped Manganites
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