The inverted hysteresis loops and exchange bias effects in amorphous/nanocrystalline Fe72Cu1V4Si15B8 ribbons at room temperature

Milica Vasic,Radoslav Surla,Dragica Minic,Nebojsa Mitrovic

doi:10.2298/sos2003283s

Milica Vasic, Radoslav Surla + Show 2 more

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https://doi.org/10.2298/sos2003283s

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Abstract

?he influence of thermally induced microstructural transformations on magnetic properties of Fe72Cu1V4Si15B8 ribbon with combined amorphous/nanocrystalline structure is presented. The experiments showed that thermally induced structural changes are in correlation with the appearance of magnetic hysteresis, i.e. with inverted hysteresis loops (IHL) and exchange bias (EB) effects. It was found that the ratio of surface to volume of a ribbon sample have an influence on hysteresis loop appearance. The inverted hysteresis loops were observed for the 1.5 mm wide and 55 ?m thick alloy samples shorter than 10 mm, but for the samples longer than 10 mm hysteresis loops were normal. With an increase of annealing temperature, a shift of the hysteresis loops measured at room temperature was noticed. The highest positive exchange bias field Heb was observed for the sample annealed at 723 K, together with the lowest magnetic field at which the changes from inverted to normal hysteresis loop occurred. Annealing at the temperature of 823 K resulted in negative Heb.

Highlights

The nanocrystalline iron based alloys obtained from the starting amorphous precursors prepared by rapidly quenching technology are interesting topics in the field of the alloy research since they have excellent soft magnetic properties [1,2,3,4]
The experiments indicate that the best soft magnetic properties were attained in the alloys with the optimum α-Fe (Si) nanocrystalline grain size, which can be evolved by controlled annealing of the starting amorphous structure
The aim of this research is to investigate the influence of thermally induced structural changes on magnetic properties of Fe72Cu1V4Si15B8 ribbons and on the inverted hysteresis loops (IHL) and the exchange bias (EB) effects that appeared

Summary

Introduction

The nanocrystalline iron based alloys obtained from the starting amorphous precursors prepared by rapidly quenching technology are interesting topics in the field of the alloy research since they have excellent soft magnetic properties [1,2,3,4]. The Fe-Cu-M-Si-B (M = Cr, V, Mo, Nb, Ta, W) „FINEMET” type аlloys with amorphous/nanocrystalline structure have been the subject of numerous scientific studies [9,10,11,12,13]. The experiments indicate that the best soft magnetic properties were attained in the alloys with the optimum α-Fe (Si) nanocrystalline grain size, which can be evolved by controlled annealing of the starting amorphous structure.

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