Magnetic properties of anisotropic Sr-La system ferrite magnets

Abstract

An experiment was carried out to investigate the effect of La/sub 2/O/sub 3/ on the magnetic and physical properties of strontium ferrite magnets. It was found that the La/sub 2/O/sub 3/ addition to SrO-6Fe/sub 2/O/sub 3/ (stoichiometric composition) was very useful in stabilizing the magnetoplumbite structure and that these ferrites of the Sr-La system had excellent permanent-magnet properties. Various compositions were tested, and the optimum conditions for making magnets and some properties of typical specimens were determined. The semisintering condition was 1250 degrees C for 1 h in oxygen, and the sintering condition 1300 degrees C for 0.5 h in oxygen. Magnetic and physical properties are presented and discussed. The ((SrO)0.143(Fe/sub 2/O/sub 3/)/sub 0.857/)/sub 98/(La/sub 2/O/sub 3/)/sub 2/ compound magnet exhibited the highest value of (BH)/sub max/, and this value was equivalent to or higher than that of ordinary Ba and Sr ferrites.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>