ELECTRON LOCALIZATION IN MIXED-VALENCE MANGANITES

Citation
Jmd. Coey et al., ELECTRON LOCALIZATION IN MIXED-VALENCE MANGANITES, Physical review letters, 75(21), 1995, pp. 3910-3913
Citations number
28
Categorie Soggetti
Physics
Journal title
ISSN journal
00319007
Volume
75
Issue
21
Year of publication
1995
Pages
3910 - 3913
Database
ISI
SICI code
0031-9007(1995)75:21<3910:ELIMM>2.0.ZU;2-A
Abstract
Mixed-valence manganites (A(0.7)(3+)B(0.3)(2+))MnO3 exhibit a resistiv ity peak with giant negative magnetoresistance below the Curie point. Residual resistivity ranges from 5 X 10(-8) to 8 X 10(3) Omega m, but the electronic heat capacity when A = Y or La is that of a normal d-ba nd metal; y approximate to 6 mJ mole(-1) K-2 Spatial fluctuations in t he Coulomb and spin-dependent potentials localize the e(g) up arrow (s igma) electrons in wave packets that are large on the scale of the Mn -Mn separation. Transport in the magnetically localized state involves zero-point-energy assisted hopping or tunneling of electrons from one weakly localized wave packet to another.