Effect of Vacuum Heat Treatment on Magnetic Ordering in Substituted Orthoferrite La1 – xSrxFeO3 – δ

The temperature dependences of the magnetization of La1 – xSrxFeO3 – δ samples (x = 0.33, 0.50, and 0.67) have been studied. Their Neel temperatures TN have been determined, at which non-collinear antiferromagnetism (weak ferromagnetism) is settled down in the samples. The introduction of a substituting impurity of strontium into La1 – xSrxFeO3 – δ and an increase in its content results in a considerable decrease in TN. This effect can be compensated using vacuum heat treatment, upon which, on the contrary, a noticeable increase in TN is observed.