ISSN:
1572-9605
Keywords:
optical conductivity
;
perovskite-type manganite
;
double exchange interaction
;
ferromagnetic metal
;
charge ordering
;
orbital ordering
Source:
Springer Online Journal Archives 1860-2000
Topics:
Electrical Engineering, Measurement and Control Technology
,
Physics
Notes:
Abstract Review is given on late optical studies on colossal magnetoresistance (CMR) manganites with perovskite or related structures. In La1−x Sr x MnO3 which undergoes a ferromagnetic transition, optical conductivity spectrum σ(ω) shows a change from a gap-like feature to metallic but highly diffussive one with increasing spin-polarization. Such a remarkable spectral weight transfer is also observed in a layered manganite, La2−2x Sr1+2x Mn2O7 (x = 0.4), with a mid-infrared peak structure due to inter-orbital $$(d_{x^2 - y^2 } \to d_{3z^2 - r^2 } )$$ transition. In Pr1−x Ca x MnO3 (x = 0.4) which undergoes the charge ordering phase transition, σ(ω) shows an anisotropic feature reflecting charge/orbital ordering pattern at 10 K. The charge-ordered state is transformed into a ferromagnetic metallic state by a magnetic field of 6.5 T at 30 K, which is manifested in a huge change of optical spectra over a wide photon-energy region (0.05 eV–3 eV).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1007708218202
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