Effects of localized holes on charge transport, local structure and spin dynamics in the metallic state of CMR La{sub 1{minus}x}Ca{sub x}MnO{sub 3}
- Los Alamos National Lab., NM (United States)
The authors review resistivity, x-ray-absorption fine-structure (XAFS) and muon spin relaxation ({mu}SR) data which provide clear evidence for localized holes causing polaron distortion and unusual spin dynamics below {Tc} in ``colossal magnetoresistive`` (CMR) La{sub 1{minus}x}Ca{sub x}MnO{sub 3}. Resistivity measurements for x = 0.33 under an applied field H have shown that ln[{rho}(H,T)] {infinity}-M, where M is the magnetization. The XAFS data show a similar functional dependence for the polaron distortions on M The data from these two measurements are interpreted in terms of some fraction of the available holes x remaining localized and some increasing fraction becoming delocalized with increasing M Finally, this polaron-induced spatial inhomogeneity yields anomalously slow, spatially inhomogeneous spin dynamics below {Tc}, as shown in the {mu}SR data. These experiments individually probe the charge, lattice and spin degrees of freedom in this CMR system and suggest that the polarons retain some identity even at temperatures significantly below {Tc}.
- Research Organization:
- Los Alamos National Lab., NM (United States)
- Sponsoring Organization:
- USDOE Assistant Secretary for Human Resources and Administration, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 650330
- Report Number(s):
- LA-UR--97-4864; CONF-971201--; ON: DE98004371
- Country of Publication:
- United States
- Language:
- English
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