ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Single crystals of La1−xSrxMnO3 with x ranging from 0.06 to 0.42 have been investigated by various techniques: resistivity and magnetoresistance, superconducting quantum interference device magnetometry, and 55Mn nuclear magnetic resonance. In addition, for two Sr concentrations, x=0.13 and 0.25, the I(V) characteristic of the oxide-metal junction has been measured versus temperature. Semiconductor-metal transition occurring just below the Curie temperature Tc was observed for x≥0.175 whereas, for x≤0.15, the crystals exhibits only semiconducting behavior, in agreement in the previous studies. These transport properties are closely connected with the electron transfer mediated by the double exchange interaction between Mn3+ and Mn4+, as revealed by 55Mn spin-echo experiments. A cusp in the magnetoresistance (MR) was observed near Tc for the crystals with x≥0.13 with typical maximum resistivity ratio R(0)/R(10 T)≈10; for the sample with x=0.1, the huge MR persists well below Tc≈140 K, which is probably due to a noncollinear spin configuration. The I(V) characteristic of the oxide-aluminum junction is strongly dependent on temperature and applied magnetic field. In the semiconducting phase, a nonlinear behavior reminiscent to that of a strongly doped dirty semiconductor is observed. © 1996 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.361723
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