Metal-semiconductor transition in the double exchange system La0.8Sr0.2Mn1−xCuxO3

Suppression of itinerant ferromagnetism and cluster-glass behaviour of colossal magnetoresistive Ta-substituted La0.67Ca0.33MnO3

“…This may be recognized as a typical feature of the various CG systems [67][68][69]. It should, however, be recalled that M FC of a canonical spin-glass is almost temperature independent below T irr [70][71][72][73]. Also T irr T c for RSG systems such as NiMn [74,75], AuFe [76] and FeZr [77], whereas for a CG system, T irr is just below T c , as observed in La 0.5 Sr 0.5 CoO 3 [78].…”

Positive and Negative Magnetoresistance in Mixed Superexchange–Double Exchange Systems

“…In this context, polaron models are often used [12], but as there is also evidence for strong spin scattering potentials [13], an extension of this formalism towards the coupling to spin polarons is indicated [14]. The prefactor r 0 usually contains information about the effective masses of the charged quasiparticles and their mobilities: 1/r 0 ¼ 2e(m n þ m p ) (2pkT/h 2 ) 3/2 (m e m h ) 3/4 for standard semiconductors, i.e., r 0 can be considered a shape function which gives combined evidence as to the type of carrierunclothed electrons, holes, spin polarons, mixed lattice and spin polarons -and their scattering centers -magnons, phonons, spin and structural defects.…”

Hydrostatic pressure effect on the metal-insulator transition in LaO0.7Ca0.3Mn1−x(Fe/Ge)xO3perovskites

“…We have found, however, that all the observable characteristic temperatures in p(T) are rather close to T, and run parallel under applied external forces. Thus, the observed correlation cannot be invalidated by an error that we could have possibly made in determining T,,, [5,6].…”