Accession Number : ADA300544
Title : Uncompensated Garnets: A Magnetic Semiconductor.
Descriptive Note : Rept. for 1 Mar 91-31 Dec 94,
Corporate Author : OHIO STATE UNIV COLUMBUS DEPT OF PHYSICS
Personal Author(s) : Wigen, Philip E.
PDF Url : ADA300544
Report Date : 09 MAY 1995
Pagination or Media Count : 36
Abstract : Yttrium iron garnet (YIG) is a ferrimagnetic oxide, Y3Fe5O12 and a good insulator. When five to ten percent of the Y(3+) is replaced by Ca(2+), an uncompensated state exists. The resulting material has perturbed magnetic properties, semiconducting electrical properties with activation energies from 0.2 to 0.4 eV and resistivities as low as 300 ohm cm at room temperature, and modified optical properties. In the past year the conductivity studies have concentrated on the evolution of a high conduction state in samples that have been annealed in a reducing atmosphere. The reduction process introduces oxygen vacancies which should compensate the hole introduced by Ca(2+). The annealing is also observed to modify significantly the effective exchange constant of the material and the optical activity. These measurements are summarized in this report.
Descriptors : *MAGNETIC PROPERTIES, *SEMICONDUCTORS, *GARNET, *YTTRIUM IRON GARNET, CALCIUM, CATIONS, OPTICAL PROPERTIES, ANNEALING, CONDUCTIVITY, INSULATION, HOLES(ELECTRON DEFICIENCIES), ELECTRICAL PROPERTIES, ROOM TEMPERATURE, REDUCTION, OXYGEN, OXIDES, EVOLUTION(GENERAL), PERTURBATIONS, ELECTRICAL RESISTANCE, COMPENSATION, EXCHANGE, MAGNETIC MATERIALS, ACTIVATION ENERGY, FERRIMAGNETISM.
Subject Categories : Geology, Geochemistry and Mineralogy
Electrical and Electronic Equipment
Electricity and Magnetism
Distribution Statement : APPROVED FOR PUBLIC RELEASE