STRUCTURAL AND MAGNETIC PROPERTIES OF NON-STOICHIOMETRIC PRASEODYMIUM MONOPHOSPHIDE

An investigation on the occurrence of non-stoichiometry in solid praseodymium monophosphide was carried out by evaluating the variation of the lattice constant and density with the composition. A range of solid solution by vacancies in the phosphorus sub-lattice was found between the compositions corresponding to PrP and PrP0.85 phases. Magnetic properties and their dependence on non-stoichiometry were determined in the temperature range 4.2°-500°K: for the quasi-stoichiometric phases there is no evidence of magnetic ordering and a superconducting transition seems to occur below 7°K, while an antiferromagnetic coupling of praseodymium ions becomes possible when the interionic distances decrease by introduction of vacancies in the phosphorus sub-lattice. © 1969.