Enhanced magnetoresistance induced by oxygen deficiency in La{sub 0.4}Ca{sub 0.6}MnO{sub 3-δ} oxides

Journal Article · Fri Mar 14 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4868315· OSTI ID:22277872

Dhahri, E. ^[1]; Hlil, E. K. ^[2]; Garden, J. L. ^[3]

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1. Laboratoire de Physique Appliquée, Faculté des Sciences de Sfax, Université de Sfax B. P. 1171, 3000 Sfax (Tunisia)
2. Institut Néel, CNRS et Université Joseph Fourier, BP 166, 38042 Grenoble (France)
3. Institut Néel, CNRS, Département MCBT, BP 166, 38042 Grenoble, Cedex 9 (France)

We report electrical features and magnetoresistance behavior of the oxygen deficient La{sub 0.4}Ca{sub 0.6}MnO{sub 3-δ} perovskites (δ = 0, 0.15, and 0.2). These samples will be referred to as S0, S15, and S20, respectively. The dependence of electrical transport on temperature and magnetic field is systematically investigated between 2 K and 400 K in magnetic field ranging up to 5 T. The parent compound shows a stable charge ordering/antiferromagnetic state with a semiconductor-like behavior in all considered temperature range. The variable range hopping and thermally activated hopping models are found to fit well with the electrical resistivity data at low and high temperatures, respectively. Oxygen deficiency tends to weaken the charge ordering and induce ferromagnetism and metallicity at low temperature. Metal insulator transition appears at higher fields for lower oxygen deficit (S15 sample) and without field for the S20 sample. The resistivity data for S15 sample are discussed in the framework of the variable-range hopping model. Abnormal transport properties were observed in the S20 sample, characterized by the double metal-insulator transitions and low minimum behavior. These results are discussed in terms of phenomenological percolation model, based on the phase segregation of ferromagnetic metallic clusters and paramagnetic insulating regions. While the parent compound shows no magnetoresistance, a large magnetoresistance is observed in the deficient samples at low temperature reaching 90% and 75% at 2 T for S15 and S20 samples, respectively. Noticeably, these values reached 98% and 91% at 5 T. The appearance of colossal magnetoresistance is attributed to the spin dependent hopping between spin clusters and/or ferromagnetic domains.

• OSTI ID: 22277872
• Journal Information: Journal of Applied Physics, Vol. 115, Issue 10; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANTIFERROMAGNETISM
CALCIUM COMPOUNDS
CUBIC LATTICES
FERROMAGNETISM
LANTHANUM COMPOUNDS
MAGNETIC FIELDS
MAGNETORESISTANCE
MANGANATES
OXYGEN
PARAMAGNETISM
PEROVSKITES
SEMICONDUCTOR MATERIALS
SPIN
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K