ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
An effective method for preparing thin films of colossal magnetoresistance (CMR) materials is by pulsed laser deposition (PLD). We have studied such films by measuring the temperature and field dependence of dc resistance, magnetization, and specifically ferromagnetic resonance (FMR). With PLD it is possible to prepare samples with reasonable homogeneity as observed with x-ray diffraction and Rutherford backscattering. However, we have found that samples that appear to be reasonably, crystalographically homogeneous are not necessarily magnetically homogeneous. We believe that a powerful technique for examining magnetic homogeneity in this class of CMR samples is via FMR. In FMR, the resonance linewidth is an indicator of the average sample homogeneity, but this technique is much more informative when used in a scanning mode that we have developed. Scanning FMR data will be shown for several CMR samples prepared from La0.7R0.3MnO3 (R=Ca, Ba) targets using PLD. We find that some complex multiline spectra (observed when the sample is measured as a whole) are actually a superposition of simpler spectra with spatially localized resonance lines. Resonance lines are also found that are present throughout the sample. The spatial variation of FMR lines we observe is a direct measure of the spatial inhomogeneity of the magnetic environment. We will discuss the FMR spatial variations as a function of sample preparation, and subsequent oxygen and argon annealing conditions. ©1997 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.364578
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