Accession Number:

ADP011912

Title:

Studies of Manganites by Magnetic Resonance Spectroscopy Methods

Descriptive Note:

Conference proceedings

Corporate Author:

POLISH ACADEMY OF SCIENCES WARSAW INSTOF PHYSICS

Report Date:

2001-01-01

Pagination or Media Count:

4.0

Abstract:

In this work, we present the studies of manganites with superfluous manganese content performed by the magnetic resonance spectroscopy methods. The ferromagnetic resonance FMR has been measured on the La0.7Ca0.31-xMn1xO3 films. The symmetrical FMR line in paramagnetic phase has the Dysonian-like shape below Tsub c. The FMR linewidth increases abruptly near the transition temperature. By comparing resonance fields oriented parallel and perpendicular to the film plane, the easy axis of magnetization was determined to be perpendicular to the film plane. In the perpendicular magnetic field, the spin-wave resonance SWR spectrum consisting of seventeenth of spin - wave modes has been observed in the La0.7Mn1.3O3 film. Two of them observed on the high-field side of SWR spectrum are connected to a surface modes. The others are the bulk nonuniform spin-wave modes. Based on a study of temperature and angular dependencies of SWR and FMR spectra, the spin-wave stiffness, g-factor and exchange constant were established. An analysis of the Mn-55 NMR spectrum in La0.6Sr0.2Mn1.2Cr0.2O3 has shown that a wide asymmetrical line can be uniquely expanded into four components with different resonance frequencies. There are manganese ions, which ionization states are close to 3 and 4, as well as the Mn ions with intermediate valence resulted from the high-frequency electron exchange.

Subject Categories:

  • Physical Chemistry
  • Electricity and Magnetism
  • Atomic and Molecular Physics and Spectroscopy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE