Correlation between MI effect and transverse anisotropy in stress-annealednanocrystalline alloys: A Mossbauer effect study

In order to understand the correlation between the large and sensitive magn eto-impedance (MI) effect in the tensile stress-annealed Fc-based nanocryst alline alloy Fe73.5Cu1Nb3Si13.5B9 and the transverse magnetic anisotropy on a microscopic scale, a Mossbauer effect study has been carried out. A seri es of ribbon samples were subject to thermal annealing with tensile stress sigma up to 60 MPa. MI measurements showed that the effective field of tran sverse magnetic anisotropy H-k increases with increasing a. Analysis of Mos sbauer spectra provided direct evidence that there is an increasing transve rse magnetic structure with increasing sigma in these tensile stress-anneal ed samples. This work confirms, on the microscopic scale, that the transver se magnetic anisotropy arises from stress-annealing and is essential for th e giant magneto-impedance effect.