Thermally induced variable-range-hopping crossover and ferromagnetism in the layered cobalt oxide Sr2Y0.5Ca0.5Co2O7

K. Yamaura; D. P. Young; R. J. Cava

doi:10.1103/PhysRevB.63.064401

Thermally induced variable-range-hopping crossover and ferromagnetism in the layered cobalt oxide Sr₂Y_0.5Ca_0.5Co₂O₇

K. Yamaura, D. P. Young, R. J. Cava

Research output: Contribution to journal › Article › peer-review

31 Scopus citations

Abstract

Temperature-dependent transport and magnetic measurements on Sr₂Y_0.5Ca_0.5Co₂O₇ indicate that ferromagnetism appears along with a crossover between two forms of variable-range-hopping (VRH) conductivity on cooling. Efros-Shklovskii (ES)-type VRH conduction was found below approximately 30 K, transformed from Mott-type VRH at higher temperature. The magnitude of the Coulomb gap and the Mott-ES VRH crossover temperature are ∼57 K and ∼170 K, respectively. These are unusually large compared to those of nonmagnetic disordered materials. The peculiar electronic state for the ferromagnetic Coulomb gap is probably due to Coulomb correlations among d electrons in the disordered system.

Original language	English (US)
Journal	Physical Review B - Condensed Matter and Materials Physics
Volume	63
Issue number	6
DOIs	https://doi.org/10.1103/PhysRevB.63.064401
State	Published - Jan 10 2001

All Science Journal Classification (ASJC) codes

Electronic, Optical and Magnetic Materials
Condensed Matter Physics

Access to Document

10.1103/PhysRevB.63.064401

Cite this

@article{4680fad596f9463cabd6c3c98fd3b4fb,

title = "Thermally induced variable-range-hopping crossover and ferromagnetism in the layered cobalt oxide Sr2Y0.5Ca0.5Co2O7",

abstract = "Temperature-dependent transport and magnetic measurements on Sr2Y0.5Ca0.5Co2O7 indicate that ferromagnetism appears along with a crossover between two forms of variable-range-hopping (VRH) conductivity on cooling. Efros-Shklovskii (ES)-type VRH conduction was found below approximately 30 K, transformed from Mott-type VRH at higher temperature. The magnitude of the Coulomb gap and the Mott-ES VRH crossover temperature are ∼57 K and ∼170 K, respectively. These are unusually large compared to those of nonmagnetic disordered materials. The peculiar electronic state for the ferromagnetic Coulomb gap is probably due to Coulomb correlations among d electrons in the disordered system.",

author = "K. Yamaura and Young, {D. P.} and Cava, {R. J.}",

year = "2001",

month = jan,

day = "10",

doi = "10.1103/PhysRevB.63.064401",

language = "English (US)",

volume = "63",

journal = "Physical Review B - Condensed Matter and Materials Physics",

issn = "1098-0121",

publisher = "American Physical Society",

number = "6",

}

TY - JOUR

T1 - Thermally induced variable-range-hopping crossover and ferromagnetism in the layered cobalt oxide Sr2Y0.5Ca0.5Co2O7

AU - Yamaura, K.

AU - Young, D. P.

AU - Cava, R. J.

PY - 2001/1/10

Y1 - 2001/1/10

N2 - Temperature-dependent transport and magnetic measurements on Sr2Y0.5Ca0.5Co2O7 indicate that ferromagnetism appears along with a crossover between two forms of variable-range-hopping (VRH) conductivity on cooling. Efros-Shklovskii (ES)-type VRH conduction was found below approximately 30 K, transformed from Mott-type VRH at higher temperature. The magnitude of the Coulomb gap and the Mott-ES VRH crossover temperature are ∼57 K and ∼170 K, respectively. These are unusually large compared to those of nonmagnetic disordered materials. The peculiar electronic state for the ferromagnetic Coulomb gap is probably due to Coulomb correlations among d electrons in the disordered system.

AB - Temperature-dependent transport and magnetic measurements on Sr2Y0.5Ca0.5Co2O7 indicate that ferromagnetism appears along with a crossover between two forms of variable-range-hopping (VRH) conductivity on cooling. Efros-Shklovskii (ES)-type VRH conduction was found below approximately 30 K, transformed from Mott-type VRH at higher temperature. The magnitude of the Coulomb gap and the Mott-ES VRH crossover temperature are ∼57 K and ∼170 K, respectively. These are unusually large compared to those of nonmagnetic disordered materials. The peculiar electronic state for the ferromagnetic Coulomb gap is probably due to Coulomb correlations among d electrons in the disordered system.

UR - http://www.scopus.com/inward/record.url?scp=0035101539&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0035101539&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.63.064401

DO - 10.1103/PhysRevB.63.064401

M3 - Article

AN - SCOPUS:0035101539

SN - 1098-0121

VL - 63

JO - Physical Review B - Condensed Matter and Materials Physics

JF - Physical Review B - Condensed Matter and Materials Physics

IS - 6

ER -

Thermally induced variable-range-hopping crossover and ferromagnetism in the layered cobalt oxide Sr₂Y_0.5Ca_0.5Co₂O₇

Abstract

All Science Journal Classification (ASJC) codes

Access to Document

Other files and links

Fingerprint

Cite this