Magnetoelastic Villari effect in Mn-Zn ferrites

The relationship between magnetic induction B, and compressive stress - sigma in Mn-Zn ferrites, of very low magnetostrictive constant lambda(s), were investigated. The Villari effect and its technical importance is discussed. It is shown that in Mn-Zn ferrites, with lambda(s) approximate to 0, the Villari point occurs for sigma approximate to 0 and that these ferrites exhibit, for \sigma \>>0, considerable magnetoelastic sensitivity - in spite of their small \lambda(s)\ value. Hence, a low magnetostriction constant lambda(s) does not exclude the possibility to apply such materials in magnetoelastic sensors. (C) 2000 Elsevier Science B.V. All rights reserved.