Stoichiometry and electronic properties of

Abstract
Treating off-stoichiometric in hydrogen transforms its electrical and magnetic properties. The untreated material is a ferromagnetic narrow-gap semiconductor () whereas the near-stoichiometric reduced material is an antiferromagnetic insulator ). Although the off-stoichiometric manganite has formally the same mixed manganese valency as compounds such as (, there is no resistivity peak at and no giant magnetoresistance. The difference may be due to potential fluctuations associated with cation vacancies.