Stress sensitivity in Ni-Mn, Ni-Mn-Co and Ni-Mn-Co-Cu ferrites

Abstract

The magnetization of the nickel ferrites with small amount of Mn, Co and Cu ions, with general formula Ni 0.98− x− y Mn 0.02 Co x Cu y Fe 2O 4, where x = 0 to 0.027 and y = 0 or 0.15, is decreased by tension, and these ferrites contract when magnetized. Stress sensitivity coefficient d = (∂B/∂ T) H = (∂S/∂H) T = (∂1/1 ∂H) T , which characterizes these properties, was determined for these ferrites. The greatest stress sensitivity ( d=-6nW/N) was observed for ferrites with the smallest magnetocrystalline anistropy, containing maximum of cobalt ( x=0.027) ions.