Nuclear magnetic resonance study of magnetic phase segregation in La1-xCaxMnO3

Citation
C. Kapusta et al., Nuclear magnetic resonance study of magnetic phase segregation in La1-xCaxMnO3, J APPL PHYS, 87(9), 2000, pp. 7121-7123
Citations number
22
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
JOURNAL OF APPLIED PHYSICS
ISSN journal
0021-8979 → ACNP
Volume
87
Issue
9
Year of publication
2000
Part
3
Pages
7121 - 7123
Database
ISI
SICI code
0021-8979(20000501)87:9<7121:NMRSOM>2.0.ZU;2-7
Abstract
A Mn-55 nuclear magnetic resonance (NMR) study of the La1-xCaxMnO3 system, 0 < x < 1, is reported. For x < 0.3 and x > 0.5 the spin echo spectra conta in resonance lines corresponding to both the microscopic ferromagnetic and antiferromagnetic regions. A resonance line near 380 MHz, which is similar to that of the spectrum of the ferromagnetic and metallic compounds (0.2 < x < 0.5) is observed for all x. This indicates the presence of clusters in which the Mn magnetic moments are double exchange coupled in the whole rang e of doping. Their hyperfine field exhibits a much weaker temperature depen dence than that of the lines of the host. This reveals the greater strength of the magnetic coupling within the clusters than in the antiferromagnetic regions and indicates a weak magnetic coupling of the clusters to the host matrix. A comparison with the NMR results on the hole doped nonstoichiomet ric compounds, LaMnO3+delta is made. The temperature dependence of the line intensities corresponding to the double exchange clusters and to the host matrix is attributed to the evolution of the magnetic phases in the compoun ds. (C) 2000 American Institute of Physics. [S0021-8979(00)66908-6].