BEHAVIOR OF Fe$sup 4+$ IN THE SYSTEM SrFeO$sub 3$-SrTiO$sub 3$
Perovskites of the system SrFeO/sub 3/ - SrTiO/sub 3/ were prepared and measurements made of their magnetic and electrical behavior. Chemical analysis showed the percentsge of Fe/sup 4+/ to very from 72.5% for SrFeO/sub 3/ to about zero for SrFe/sub 0.1/ Ti/sub 0.9/O/sub 3/; the rest of the iron was in the Fe< s3>s/sup +/ state and electrical balance was achieved by oxygen loss. SrFe/sub 1- x/ Ti/sub x/O/sub 3/ was artiferromagnetic between x = 0 and x = 0.9, with a Neel temperature below 60 deg K. A parasitic ferromagnetic component developed when these compounds were cooled in a magnetic field. Its magnitude depended on the temperature and on the magnetic field applied during cooling; its pesk value was 0.995 emu/g for x = 0.1. De tailed studies were made on SrFe/sub 0.8/Ti/sub 0.2/ O/sub 3/. The cond uctivity of these perovskites ranged from 10/sup -8/ mho/cm for x = 1.0 to 10/sup -2/ for x = 0.0 and showed a marked break at x = 0.8. SrFeO/sub 3/ was an n-type semiconductor; with the addition of Ti/sup 4+/ the sign of the thermoelectric voltage changed to p type. The activation energy decreased from 0.79 ev for SrTiO/sub 3/ to 0.05 ev for SrFeO/sub 3/. The Fe/sup 4+/ cortent depended on the heat treatment and atmosphere during formation. (auth)
- Research Organization:
- Massachusetts Inst. of Tech., Cambridge. Lab. for Insulation Research
- NSA Number:
- NSA-15-016872
- OSTI ID:
- 4038453
- Report Number(s):
- NP-10105
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ANTIFERROMAGNETIC MATERIALS
ANTIFERROMAGNETISM
ATMOSPHERE
BEHAVIOR
CALCIUM OXIDES
CHEMISTRY
COOLING
ELECTRIC CONDUCTIVITY
FERRATES
FERROMAGNETIC MATERIALS
HEAT TREATMENTS
IONS
IRON
IRON OXIDES
MAGNETIC FIELDS
MAGNETISM
MEASURED VALUES
MINERALS
NEEL TEMPERATURE
PEROVSKITE
PREPARATION
SEMICONDUCTORS
STRONTIUM COMPOUNDS
TEMPERATURE
THERMOELECTRICITY
TITANATES
TITANIUM OXIDES
TRANSITION TEMPERATURE