Emergence of size induced metallic state in the ferromagnetic insulating Pr0.8Sr0.2MnO3 manganite: Breaking of surface polarons

2015 ◽  
Vol 8 (2) ◽  
pp. 2084-2093 ◽  
Author(s):  
PROLOY TARAN DAS ◽  
Arun Kumar Nigam ◽  
Tapan Kumar Nath
Keyword(s):  
Transport Properties ◽  
Metallic State ◽  
Temperature Dependent ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
System A ◽  
Surface Disorder ◽  
Bulk System ◽  
Magnetic Transport ◽  
Grain Surface

Nano-dimensional effects on electronic-, magneto-transport properties of granular ferromagnetic insulating (FMI) Pr0.8Sr0.2MnO3 (PSMO) manganite (down to 40 nm) have been investigated in details. From the electronic and magnetic transport properties, a metallic state has been observed in grain size modulation by suppressing the ferromagnetic insulating state of PSMO bulk system. A distinct metal-insulator transition (MIT) temperature around 150 K has been observed in all nanometric samples. The observed insulator to metallic transition with size reduction can be explained with surface polaron breaking model, originates due to enhanced grain surface disorder. This proposed phenomenological polaronic model plays a significant role to understand the polaronic destabilization process on the grain surface regime of these phase separated nano-mangnatie systems. Temperature dependent resistivity and magnetoresistance data in presence of external magnetic fields are investigated in details with various compatible models.

Tight-Binding Model for DNA Double Chains: Metal–Insulator Transition Due to the Formation of a Double Strand of DNA

1997 ◽  
Vol 11 (20) ◽  
pp. 2405-2423 ◽  
Author(s):  
Kazumoto Iguchi
Keyword(s):  
Electronic Structure ◽  
Finite Temperature ◽  
Deoxyribonucleic Acid ◽  
Recent Observation ◽  
Tight Binding ◽  
Tight Binding Model ◽  
Metal Insulator Transition ◽  
Binding Model ◽  
Metal Insulator ◽  
System A

A tight-binding model is formulated for the calculation of the electronic structure of a double strand of deoxyribonucleic acid (DNA). The theory is applied to DNA with a particular structure such as the ladder and decorated ladder structures. It is found that there is a novel type of metal–insulator transitions due to the hopping anisotropy of the system. A metal-semimetal-semiconductor transition is found in the former and an effective semiconductor-metal transition at finite temperature in the latter, as the effect of base paring between two strands of DNA is increased. The latter mechanism may be responsible for explaining the Meade and Kayyem's recent observation.

Transport properties of two-dimensional hole gas in a Ge1−x Si x /Ge/Ge1−x Si x quantum well in the vicinity of metal-insulator transition

2007 ◽  
Vol 41 (11) ◽  
pp. 1315-1322 ◽  
Author(s):  
Yu. G. Arapov ◽  
V. N. Neverov ◽  
G. I. Harus ◽  
N. G. Shelushinina ◽  
M. V. Yakunin ◽  
...  
Keyword(s):  
Quantum Well ◽  
Transport Properties ◽  
Insulator Transition ◽  
Two Dimensional ◽  
Metal Insulator Transition ◽  
Metal Insulator

scholarly journals Identification of a monoclinic metallic state in VO2 from a modified first-principles approach

2019 ◽  
Vol 33 (12) ◽  
pp. 1950148
Author(s):  
Yongcheng Liang ◽  
Ping Qin ◽  
Zhiyong Liang ◽  
Lizhen Zhang ◽  
Xun Yuan ◽  
...  
Keyword(s):  
First Principles ◽  
Lattice Distortion ◽  
Insulator Transition ◽  
Metallic State ◽  
Strongly Correlated ◽  
Electron Systems ◽  
First Principles Calculations ◽  
Monoclinic Structure ◽  
Metal Insulator Transition ◽  
Metal Insulator

Metal-insulator transition (MIT) underlies many remarkable and technologically important phenomena in VO2. Even though its monoclinic structure had before been the reserve of the insulating state, recent experiments have observed an unexpected monoclinic metallic state. Here, we use a modified approach combining first-principles calculations with orbital-biased potentials to reproduce the correct stability ordering and electronic structures of different phases of VO2. We identify a ferromagnetic monoclinic metal that is likely to be the experimentally observed mysterious metastable state. Furthermore, the calculations show that an isostructural insulator-metal electronic transition is followed by the lattice distortion from the monoclinic structure to the rutile one. These results not only explain the experimental observations of the monoclinic metallic state and the decoupled structural and electronic transitions of VO2, but also provide a useful understanding for the metal-insulator transition in other strongly correlated d electron systems.

Magnetic, Electronic - and Magneto - Transport Properties of Nanocrystalline Nd0.6Sr0.4MnO3 Manganites

2009 ◽  
Vol 67 ◽  
pp. 131-136 ◽  
Author(s):  
Kundu Sourav ◽  
Kumar Nath Tapan
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Transition Temperature ◽  
Curie Temperature ◽  
Transport Properties ◽  
Significant Variation ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Low Field

We have reported in this paper, the effect of grain size in Nd0.6Sr0.4MnO3 .We have investigated the effect of grain size on metal-insulator transition and Curie temperature. We have also reported here the variation of low field magnetoresistance with temperature and grain size. We have observed that the Curie temperature increases monotonically with particle size. The metal insulator transition temperature initially increases with particle size and then gets fixed to a certain value. In these Nd0.6Sr0.4MnO3 nanometric systems, any significant variation of magnetoresistance with particle size is not observed.

TRANSPORT PROPERTIES OF Ag-DOPED La0.7Ca0.3MnO3 THIN FILMS ON SILICON SUBSTRATE

2010 ◽  
Vol 24 (27) ◽  
pp. 5451-5456 ◽  
Author(s):  
H. C. JIANG ◽  
W. L. ZHANG ◽  
X. F. CAO ◽  
W. X. ZHANG ◽  
B. PENG
Keyword(s):  
Thin Films ◽  
Transition Temperature ◽  
Transport Properties ◽  
Silicon Substrate ◽  
Annealing Temperature ◽  
Rf Magnetron Sputtering ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Higher Temperature

Ag -doped La 0.7 Ca 0.3 MnO 3 (LCMO) films were prepared on silicon substrate by RF magnetron sputtering. The dependences of transport properties on annealing temperature were explored. It is shown that the resistivity of the samples decreases and the metal–insulator transition temperature shifts to higher temperature with the increase in annealing temperature. Two metal–insulator transition temperatures are presented in the R – T plots of Ag -doped LCMO films, which can be explained by the Ag 1+ substitution of La 3+ to form La 1-x Ag x MnO 3 compound. Compared with LCMO thin films, Ag -doping can observably improve the TM-I and decrease the resistivity of the samples.

Temperature-dependent photoemission and x-ray absorption studies of the metal-insulator transition inBi1−xLaxNiO3

2007 ◽  
Vol 76 (20) ◽  
Author(s):  
Hiroki Wadati ◽  
Kiyohisa Tanaka ◽  
Atsushi Fujimori ◽  
Takashi Mizokawa ◽  
Hiroshi Kumigashira ◽  
...  
Keyword(s):  
Insulator Transition ◽  
Temperature Dependent ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
X Ray ◽  
Absorption Studies ◽  
X Ray Absorption

The Influence of Local Magnetization on Transport in Cd0.91Mn0.09Te:In

1992 ◽  
Vol 290 ◽  
Author(s):  
S. Von Molnar ◽  
T. Penney ◽  
I. Terry ◽  
P. Becla
Keyword(s):  
Transport Properties ◽  
Carrier Concentration ◽  
Magnetic Semiconductors ◽  
Localization Length ◽  
Insulator Transition ◽  
Local Magnetization ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Magnetic Polarons ◽  
Transport Effect

AbstractWe describe the influence of local magnetization on electron localization and transport properties on the insulating side of the metal insulator transition in the dilute magnetic persistent photoconductor Cd0.091 Mn0.09Te:ln. Measurements of both the temperature dependence of the transport properties, and also the dielectric constant, are reported for just one sample in which the carrier concentration n was varied by photodoping. From these results we are able to extract the carrier concentration dependence of the localization length and the permitivity of the electrons. We also report onl a new transport effect which occurs at ultra low temperatures and/or carrier concentrations very close to the metal insulator transition. We find that this mechanism is totally magnetic in origin and are able to explain it in terms of the well devewloped ideas of magnetic polarons in magnetic semiconductors.

scholarly journals Fabrication and Transport Properties of Manganite-Polyacrylamide-Based Composites

2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
Viorel Sandu ◽  
Stelian Popa ◽  
Ion Ivan ◽  
Carmen Plapcianu ◽  
Elena Sandu ◽  
...  
Keyword(s):  
Transport Properties ◽  
Insulator Transition ◽  
Electric Transport ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Poly Acrylamide

We present the fabrication and transport properties of a series of composites made ofLa2/3Sr1/3MnO3and acrylamide-based copolymers. The most important result is the very narrow transition, of only 27 K, displayed by the peak that appears around the metal-insulator transition of the composites made with poly(acrylamide-vinylacetate). Although the amount of polymer is rather low, different copolymers change drastically the electric transport characteristics.

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