ELECTRICAL RESISTIVITIES AND MAGNETIC SUSCEPTIBILITIES OF SOME RARE EARTH METAL-METAL HALIDE SYSTEMS. Thesis
In order to verify the electronic structure of rare earth metal-- metal halide systems, the magnetic susceptibilities and electrical resistivities of certain compounds were measured. The susceptibilities of NI/sub 1.95/ and NdCl/ sub 2.04/ do not obey the Curie-Weiss law although there is an asymptotic approach to this behavior at low temperatures (<200 deg K). The data are consistent with the 4f/sup 4/ configuration for the Nd/sup 2+/ cation and indicate a low-lying excited state. The energy separation between the ground and excited states is equivalent to 1400 deg K. The calculated magnetic moments of the ground and excited states are 2.87 and 5.38 Bohr magnetons, respectively. Data for NdCl/sub 3/ and Ndl/sub 3/ are also presented ( mu = 3.78 and 3.72 B.M., respectively). The resistivity of LaI/sub 2/ is 60 mu -ohm-cm at 25 deg C and decreases to about 10 mu -ohm-cm at 78 deg K. The compound has a small, essentially temperature independent paramagnetism with a magnitude typical of the Pauli paramagnetism of metals. The results confirm the presence of a metallic conduction band in LaI/sub 2/ and preclude the existence of the discrete La/sup 2+/ cation in this compound. However, there is magnetic evidence that such an ion may be present in LaI/sub 2.4/. Some resistivity results for CeI/sub 2/ and PrI/sub 2/ are also discussed. The specific conductivities of the PrI/sub 3/ + Pr and NdI/sub 3/ + Nd melts were determined over the complete solubility range. The results for the Nd system are typical of ionic mixtures although there are significant positive deviations from additivity. Some electronic conduction is evident in the Pr melts, the conductivity rising to 19 (ohmcm)/sup -1/ at 26.8 mole% Pr. The implications of the temperature coefficient of conductivity on the conduction mechanism are discussed. The contrasting propenties of the compounds and melts were interpreted as resulting from a competition D and F states (defined by whether the extra electron is placed in a 5d or 4f orbital) with the F state becoming more stable as the series La to Eu is traversed. (TCO)
- Research Organization:
- Originating Research Org. not identified
- NSA Number:
- NSA-18-004281
- OSTI ID:
- 4124956
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-64
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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Related Subjects
ATOMIC MODELS
ATOMS
BOHR MAGNETON
CATIONS
CERIUM IODIDES
CURIE-WEISS LAW
ELECTRIC CONDUCTIVITY
ELECTRONS
ENERGY
FERROMAGNETIC MATERIALS
HALIDES
IONS
LANTHANUM IODIDES
LOW TEMPERATURE
MAGNETIC MOMENTS
MAGNETISM
MEASURED VALUES
NEODYMIUM
NEODYMIUM CHLORIDES
NEODYMIUM IODIDES
PRASEODYMIUM
RARE EARTHS
SOLUBILITY
SUSCEPTIBILITY
TEMPERATURE