Ir doped CrO2: The ideal magnetic particle

The magnetic properties of Ir doped CrO2particles have been shown [2], [3] to be governed by coherent rotational switching processes and very large coercive forces. These effects arise as a result of the single ion anisotropy of the Ir atoms. It is now shown that the interaction field factor decreases very rapidly as the Ir content increases, reaching 6% of the value of pure CrO2at 5% Ir. Hence these particles are ideal in two senses. Experimental measurements regarding the interaction effects are proposed and the relationship of these results to those for Co containing γ-Fe2O3is outlined.