Red Shift in Optical Absorption Tall and Superparamagnetism of gamma-Fe2O3 Nanoparticles in a Polymer Matrix
Abstract
Well defined spherical particles of gamma - Fe2O3 have been synthesized in the pores of a polymer matrix in the form of beads by an ion exchange and precipitation reaction. The particle size distribution is a gaussian with an average diameter of 80 A. The DC magnetic susceptibility and the magnetization of the nanocomposite has been measured between 4 and 300 K using a Faraday balance and a magnetometer, respectively. The magnetic measurements demonstrate that the particles are superparamagnetic with a blocking temperature T about 55 K. The optical absorption edge of the mesoscopic system is red shifted with respect to single crystal films of gamma - Fe2O3 with an absorption tail extended deeply in the gap. Although lattice distortion and existence of excitonic states in the gap can explain the absorption behavior, the red shift can successfully be explained by the quantum confinement of an electron-hole pair in a spherical well.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2003
- Accession Number
- ADP014282
Entities
People
- James J. Davis
- Jens W. Otto
- John K. Vassiliou
- V. Mehrotra
Organizations
- Villanova University