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Jaime, M.; Lin, P.; Salamon, M. B.; Han, Peng

doi:10.1103/physrevb.58.r5901

Cited by 134 publications

(102 citation statements)

References 30 publications

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“…A very similar form has been observed for the halfmetallic, colossal-MR manganites. 19 For CrO 2 , the temperature ⌬ is clearly too low to be related directly to the band gap of order 1 eV predicted by any of the bandstructure calculations. Perpendicular ͑field perpendicular to the film plane͒ and longitudinal ͑field in-plane and parallel to the current͒ MR measurements on sample F57 are shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…37. Single magnon scattering in the manganites ͑which may have a small number of minority states at E F even at 0 K͒ was studied by Jaime et al 19 They relate the suppression of the T 2 term in the resistivity to the minimum magnon energy Dq min (D is the spin-wave stiffness constant͒ which connects the majority and minority band Fermi momentum vectors k F↑ and k F↓ . A more recent model 38 considers the ''nearly'' half-metallic ferromagnet ͑namely, the manganites͒, and stipulates that the minority spin band at E F does not conduct because of Anderson localization.…”

Section: Discussionmentioning

confidence: 99%

“…They all predict essentially an onset of spin disorder scattering at temperatures of order 100 K, above which the resistivity increases as T 2 or T 2.5 . Both of the latter manganite models 19,38 refer to a mechanism for the negative, nonsaturating MR. In Ref.…”

Section: Discussionmentioning

confidence: 99%

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Evidence for two-band magnetotransport in half-metallic chromium dioxide

et al. 2000

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Magnetotransport measurements were made on patterned, ͑110͒ oriented CrO 2 thin films grown by the high-pressure, thermal decomposition of CrO 3 onto rutile substrates. The low-temperature Hall effect exhibits a sign reversal from positive to negative as the magnetic field is increased above 1 T, which may be interpreted within a simple two-band model as indicating the presence of highly mobile ( h ϭ0.25 m 2 /V s) holes as well as a much larger number of less mobile electrons (nϭ0.4 electrons/Cr͒. Between 50 and 100 K, the field at which the sign reversal occurs rapidly increases and a contribution from the anomalous Hall effect becomes significant, while the large, positive transverse magnetoresistance ͑MR͒ observed at low temperatures changes over to a predominantly negative MR. These changes correlate with a thermally activated dependence in the resistivity of the form T 2 e Ϫ⌬/T with ⌬Ϸ80 K, reflecting the lack of temperature dependence in the resistivity at low temperatures and a T 2 behavior above 100 K. The high mobilities at low temperature which result in the observed positive MR reflect the suppression of spin-flip scattering expected for a half-metallic system. However, the changes in magnetotransport above the temperature ⌬ must be due to the onset of spin-flip scattering, even though k B ⌬ is much less than the expected energy gap in the minority spin density of states. The significance of ⌬ is discussed in terms of recent models for another half-metallic system, the perovskite manganites, and the possible formation of ''shadow bands.''

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Evidence for two-band magnetotransport in half-metallic chromium dioxide

et al. 2000

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“…1,2,3,4,5,6 Recent studies on single crystals of the three-dimensional 3D pseudocubic compounds R 1−x A x MnO 3 (R is a trivalent rare-earth ion and A is a divalent alkaline-earth ion) show a T 2 dependence of the resistivity, 2,3,4 which has been interpreted as either electron-electron 3,4 or one-magnon 2 scattering. However, low-temperature resistivity measurements of epitaxial thin films of La 1−x Ca x MnO 3 provide support for the presence of small-polaron conduction in the ferromagnetic (FM) state.…”

Section: Introductionmentioning

confidence: 99%

Low-temperature electrical transport in bilayer manganiteLa1.2Sr1.8Mn<

et al. 2002

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The temperature T and magnetic field H dependence of anisotropic in-plane ρ ab and out-of-plane ρc resistivities have been investigated in single crystals of the bilayer manganite La1.2Sr1.8Mn2O7. Below the Curie transition temperature Tc = 125 K, ρ ab and ρc display almost the same temperature dependence with an up-turn around 50 K. In the metallic regime (50 K ≤ T ≤ 110 K), both ρ ab (T ) and ρc(T ) follow a T 9/2 dependence, consistent with the two-magnon scattering. We found that the value of the proportionality coefficient B f it ab and the ratio of the exchange interaction J ab /Jc obtained by fitting the data are in excellent agreement with the calculated B ab based on the twomagnon model and J ab /Jc deduced from neutron scattering, respectively. This provides further support for this scattering mechanism. At even lower T , in the non-metallic regime (T < 50 K), both the in-plane σ ab and out-of-plane σc conductivities obey a T 1/2 dependence, consistent with weak localization effects. Hence, this demonstrates the three-dimensional metallic nature of the bilayer manganite La1.2Sr1.8Mn2O7 at T < Tc.

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“…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.…”

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confidence: 87%

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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Low-temperature electrical transport and double exchange inLa0.67(Pb,Ca<

Cited by 134 publications

References 30 publications

Evidence for two-band magnetotransport in half-metallic chromium dioxide

Evidence for two-band magnetotransport in half-metallic chromium dioxide

Low-temperature electrical transport in bilayer manganiteLa1.2Sr1.8Mn<

Spin-wave scattering at low temperatures in manganite films

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