Origin of colossal magnetoresistance in LaMnO3 manganite.
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.
High Pressure Synergetic Consortium, Geophysical Laboratory,Carnegie Institution of Washington, Argonne, IL 60439; mbaldini@carnegiescience.edu mao@gl.ciw.edu.
Maria
M
Baldini
Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015;
Takaki
T
Muramatsu
Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, Cantoblanco, E-28049 Madrid, Spain;
Mohammad
M
Sherafati
Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015; Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China; mbaldini@carnegiescience.edu mao@gl.ciw.edu.
Ho-kwang
HK
Mao
Department of Chemistry, University of Pavia, I-27100 Pavia, Italy; Italian National Consortium for Materials Science and Technology, University of Pavia Research Unit, I-27100 Pavia, Italy;
Lorenzo
L
Malavasi
Department of Physics, University of Rome "Sapienza," I-00185 Rome, Italy;
Paolo
P
Postorino
Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211.
Sashi
S
Satpathy
Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015;
Viktor V
VV
Struzhkin
colossal magnetoresistance; high pressure; phase separation; strongly correlated materials; transport measurements