Giant magnetoresistance in La1−xSrxMnOz films near room temperature

Ju, Honglyoul; Kwon, C.; Li, Qi; Greene, R. L.; Venkatesan, T.

doi:10.1063/1.112808

Cited by 471 publications

(166 citation statements)

References 15 publications

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] In the doping range 0.2 < x < 0.5, these compounds are known to undergo a double phase transition from paramagnetic (PM) insulator (I) to ferromagnetic (FM) metal (M) state characterized by the Curie temperature T C and the charge carrier localization temperature T MI , respectively. The so-called giant magnetoresistivity (GMR) exhibits a sharp peak around T MI , while below T C the system acquires a spontaneous magnetization accompanied by a giant magnetic entropy changes.…”

Section: Introductionmentioning

confidence: 99%

Estimation of the charge carrier localization length from Gaussian fluctuations in the magneto-thermopower ofLa0.6Y0.1
Sergeenkov
¹
,
Bougrine
²
,
Ausloos
³

et al. 1999
Phys. Rev. B
11
4
24
0
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Section: Introductionmentioning

confidence: 99%

Estimation of the charge carrier localization length from Gaussian fluctuations in the magneto-thermopower ofLa0.6Y0.1
Sergeenkov
¹
,
Bougrine
²
,
Ausloos
³

et al. 1999
Phys. Rev. B
11
4
24
0
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“…The magnetization M was measured in a magnetic field parallel to the film plane using a Quantum Design Superconducting Quantum Interference Device (SQUID) magnetometer. is close to the values of 270 and 290 K, obtained for as-grown and annealed in N 2 gas films, respectively, with same composition [22]. The T MI of 188 K for the 2000Å La 0.8 Sr 0.2 MnO 3 film is lower than that for single crystal specimens [8].…”

mentioning

confidence: 73%

Spin-wave scattering at low temperatures in manganite films

et al. 2003

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The temperature T and magnetic field H dependence of the resistivity ρ has been measured for La0.8−ySr0.2MnO3 (y=0 and 0.128) films grown on (100) SrTiO3 substrates. The low-temperature ρ in the ferromagnetic metallic region follows well ρ(H, T ) = ρ0(H) + A(H)ωs/ sinh(hωs/2kBT ) + B(H)T 7/2 with ρ0 being the residual resistivity. We attribute the second and third term to smallpolaron and spin-wave scattering, respectively. Our analysis based on these scattering mechanisms also gives the observed difference between the metal-insulator transition temperatures of the films studied. Transport measurements in applied magnetic field further indicate that spin-wave scattering is a key transport mechanism at low temperatures. The observation of colossal magnetoresistance CMR effect in manganite films [1] has produced a resurgence of interest in these materials for both fundamental physics and their possible application in recording media and magnetic switching devices. The microscopic transport mechanism in these materials has long been thought to be double exchange DE [2,3,4]. However, it has been realized [5] that the effective carrier-spin interaction in the DE model is too weak to lead to a significant reduction of the electronic bandwidth, which would justify the observed several orders of magnitude increase in conductivity just below the Curie temperature T C . Indeed, a large number of experiments have shown that the DE scenario alone cannot account for the properties of the manganites and that CMR is not purely electronic in origin [6,7].Low-temperature charge transport measurements of manganites in the ferromagnetic metallic state are essential in clarifying the specific mechanisms responsible for the CMR effect. At low temperatures, a dominant T 2 term in resistivity has generally been observed [8,9,10]. Although the T 2 behavior is consistent with electronelectron interaction [11], the coefficient of the T 2 term is about 60 to 70 times larger than the one expected for electron-electron scattering [12]. Moreover, a careful check of the low-temperature resistivity [13,14] has shown substantial deviation from the T 2 −like behavior in the very low temperature region. Other power-law temperature dependences of the resistivity have also been reported [10,14,15,16,17,18,19]. At present, there is no agreement on the actual scattering mechanism below the Curie temperature.Here, we address the low-temperature scattering mechanism in manganites through resistivity measurements of La 0.8−y Sr 0.2 MnO 3 (y = 0 and 0.128) films grown on SrTiO 3 substrates, measured in zero field as well as applied magnetic fields up to 14 T. Our data indicate that spin-wave scattering, which gives a T 7/2 dependence in the low-temperature resistivity, is a dominant dissipation mechanism in the ferromagnetic state of these manganites, besides scattering of small polarons by a soft optical phonon mode. Our analysis of the resistivity data in terms of small-polaron and spin-wave scattering mechanisms, and the spin fluctuation model also g...

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“…Work in the 1950s and 1960s elucidated the nature of the magnetic ordering in these systems [1][2][3] and uncovered the role of the double-exchange mechanism in stabilizing ferromagnetic phases [4][5][6]. Recent work, motivated by the observation [7][8][9][10][11][12] of colossal magnetoresistance (CMR) in this class of compounds, has focused on their intriguing magnetic and conduction properties. We refer the reader to recent reviews [13,14] for a survey of such studies.…”

Section: Introductionmentioning

confidence: 99%

Mean-field theory of charge ordering and phase transitions in the colossal-magnetoresistive manganites

Mishra

Pandit

Satpathy

1999

J. Phys.: Condens. Matter

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Abstract. We study phase transitions in the colossal-magnetoresistive manganites by using a mean-field theory both at zero and non-zero temperatures. Our Hamiltonian includes doubleexchange, superexchange, and Hubbard terms with on-site and nearest-neighbour Coulomb interaction, with the parameters estimated from earlier density-functional calculations. The phase diagrams show magnetic and charge-ordered (or charge-disordered) phases as a result of the competition between the double-exchange, superexchange, and Hubbard terms, the relative effects of which are sensitively dependent on parameters such as doping, bandwidth, and temperature. In accord with the experimental observations, several important features are reproduced from our model, namely, (i) a phase transition from an insulating, charge-ordered antiferromagnetic to a metallic, charge-disordered ferromagnetic state near dopant concentration x = 1/2, (ii) the reduction of the transition temperature T AF→F by the application of a magnetic field, (iii) melting of the charge order by a magnetic field, and (iv) phase coexistence for certain values of temperature and doping. An important feature, not reproduced in our model, is the antiferromagnetism in the electron-doped systems, e.g., La 1−x Ca x MnO 3 over the entire range of 0.5 x 1, and we suggest that a multi-band model which includes the unoccupied t 2g orbitals might be an important ingredient for describing this feature.

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Giant magnetoresistance in La1−xSrxMnOz films near room temperature

Cited by 471 publications

References 15 publications

Estimation of the charge carrier localization length from Gaussian fluctuations in the magneto-thermopower ofLa0.6Y0.1
Sergeenkov
¹
,
Bougrine
²
,
Ausloos
³

et al. 1999
Phys. Rev. B
11
4
24
0
View full text Add to dashboard Cite

Estimation of the charge carrier localization length from Gaussian fluctuations in the magneto-thermopower ofLa0.6Y0.1
Sergeenkov
¹
,
Bougrine
²
,
Ausloos
³

et al. 1999
Phys. Rev. B
11
4
24
0
View full text Add to dashboard Cite

Spin-wave scattering at low temperatures in manganite films

Mean-field theory of charge ordering and phase transitions in the colossal-magnetoresistive manganites

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Giant magnetoresistance in La1−xSrxMnOz films near room temperature

Cited by 471 publications

References 15 publications

Estimation of the charge carrier localization length from Gaussian fluctuations in the magneto-thermopower ofLa0.6Y0.1Sergeenkov1, Bougrine2, Ausloos3 et al. 1999Phys. Rev. B114240View full textAdd to dashboardCite

Estimation of the charge carrier localization length from Gaussian fluctuations in the magneto-thermopower ofLa0.6Y0.1Sergeenkov1, Bougrine2, Ausloos3 et al. 1999Phys. Rev. B114240View full textAdd to dashboardCite

Spin-wave scattering at low temperatures in manganite films

Mean-field theory of charge ordering and phase transitions in the colossal-magnetoresistive manganites

Contact Info

Product

Resources

About

Estimation of the charge carrier localization length from Gaussian fluctuations in the magneto-thermopower ofLa0.6Y0.1
Sergeenkov
¹
,
Bougrine
²
,
Ausloos
³

et al. 1999
Phys. Rev. B
11
4
24
0
View full text Add to dashboard Cite

Estimation of the charge carrier localization length from Gaussian fluctuations in the magneto-thermopower ofLa0.6Y0.1
Sergeenkov
¹
,
Bougrine
²
,
Ausloos
³

et al. 1999
Phys. Rev. B
11
4
24
0
View full text Add to dashboard Cite