The influence of dynamic surface fields on the coercive field and energy loss of amorphous Co_70.3Fe_4.7Si_15B_10 ribbon

The M-H loops obtained under different magnetization conditions have been used in order to analyze the coercive field H_c and the energy loss per cycle E for the amorphous Co_70.3Fe_4.7Si_15B_10 ribbon. Applying the model for the influence of the surface fields Hp on the magnetization processes in amorphous ferromagnetic ribbons, we investigated the effects of the dynamic field H_p on H_c and E. It is shown that the influence of dynamic H_p on the M-H loop does not depend on the origin of H_c and E (static or dynamic). This result is important both for the future investigations of the magnetization processes in these materials and for the potential applications

The model for the magnetization of current carrying amorphous ferromagnets

A recent model for the explanation of the decrease of coercive field H_c and the core loss E in amorphous ribbons carrying a direct current J_d has been extended in order to account for the effects of an alternating core current J. The model predicts a linear decrease of H_c with the amplitude J_0 of J and the achievement of H_c=0 for J_0 which is sufficient in order to release the domain walls responsible for H_c in the absence of the drive field H. The actual shape and frequency of the core current pulses appear to be immaterial as long as the condition J=J_0 at H = 0 is fulfilled. The accurate measurements performed on the stress-free Co_70.3Fe_4.7Si_15B_10 and twisted Fe_80B_20 ribbons confirm the validity of the model. Some applications of the phenomenon are briefly discussed

Study of the position of the domain wall pinning centres within the Co_70.3Fe_4.7Si_15B_10 amorphous ribbons

Variations of the positions and strengths of the domain wall pinning centres within an amorphous Co_70.3Fe_4.7Si_15B_10 ribbon were studied by means of a model for the influence of the surface fields Hp on the process of magnetization of amorphous ribbons. The strongest pinning centres are situated close to the free surface of the ribbon and the strength of the pinning centres decreases towards its centre

Influence of the successive annealing on the magnetization processes in Fe_73.5Cu_1Nb_3Si_15.5B_7 ribbon

The model for the influence of core-current generated field Hp on the magnetization processes in ferromagnetic ribbons has been employed for the detailed analysis of the M-H loops and the corresponding dM/dt vs. H curves for Fe_73.5Cu_1Nb_3Si_15.5B_7 alloy, successively annealed at different temperatures

Study of the position of the domain wall pinning centres within the Co_70.3Fe_4.7Si_15B_10 amorphous ribbons

Variations of the positions and strengths of the domain wall pinning centres within an amorphous Co_70.3Fe_4.7Si_15B_10 ribbon were studied by means of a model for the influence of the surface fields Hp on the process of magnetization of amorphous ribbons. The strongest pinning centres are situated close to the free surface of the ribbon and the strength of the pinning centres decreases towards its centre

The origin of the reduction of loss in current-carrying ferromagnets

A simple model for the explanation of the decrease of coercive field Hc and loss E in magnetic ribbons carrying an electric current has been proposed. For lower currents accurate measurements performed on amorphous Co_70.3Fe_4.7B_10Si_15 ribbon confirm the validity of the model. The results for higher currents can also be explained in terms of the same model providing that the influence of the perpendicular field (caused by the current flow) on the actual domain structure is taken into account. Based on the model predictions a new type of soft magnetic material is proposed

Utjecaj dinamičkih površinskih polja na koercitivno polje i gubitke energije u amorfnoj vrpci Co70.3Fe4.7Si15B10

The M-H loops obtained under different magnetization conditions have been used in order to analyze the coercive field Hc and the energy loss per cycle E for the amorphous Co70.3Fe4.7Si15B10 ribbon. Applying the model for the influence of the surface fields Hp on the magnetization processes in amorphous ferromagnetic ribbons, we investigated the effects of the dynamic field Hp on Hc and E. It is shown that the influence of dynamic Hp on the M-H loop does not depend on the origin of Hc and E (static or dynamic). This result is important both for the future investigations of the magnetization processes in these materials and for the potential applications.Gubitke energije E po jednom ciklusu te koercitivno polje Hc proučavali smo analizom M-H krivulja dobivenih u različitim uvjetima magnetiziranja amorfne vrpce Co70.3Fe4.7Si15B10. Primjenom modela za utjecaj površinskih polja Hp na procese magnetiziranja amorfnih feromagnetskih vrpci proučavali smo utjecaj dinamičkih Hp na E i Hc . Pokazuje se da taj utjecaj ne ovisi o porijeklu Hc i E (statički ili dinamički) što je važna činjenica kako za daljnje istraživanje tako i za primjenu ovakvih materijala

The origin of the surface field enhanced coercive field in nanophase Fe_73.5Cu_1Nb_3Si_15.5B_7 ribbon

The influence of surface fields H_p (generated with either direct or alternating core-current) on soft magnetic properties of amorphous and nanocrystalline Fe_73.5Cu_1Nb_3Si_15.5B_7 ribbon has been studied. While in amorphous ribbon the coercive field H_c decreases with H_p, in the same optimally annealed ribbon (H_c = 1.3 A/m, M_m ≈ M_s) H_c increases with H_p and the hysteresis loss E decreases with H_p for all explored types of H_p (static and dynamic with different phases with respect to that of the magnetizing field H). The unexpected increase of H_c in nanocrystalline ribbon is associated to the influence of H_p on the surface and main (inner) domain structure. The model is developed which takes into account this interaction and explains all experimental results. The probable adverse effect of the external fields with configurations similar to those of H_p on the performance of such ribbons is briefly discussed and some procedures which can prevent these effects are proposed

Model magnetiziranja amorfnog feromagneta kojim teče struja

A recent model for the explanation of the decrease of coercive field Hc and the core loss E in amorphous ribbons carrying a direct current Jd has been extended in order to account for the effects of an alternating core current J. The model predicts a linear decrease of Hc with the amplitude J0 of J and the achievement of Hc=0 for J0 which is sufficient in order to release the domain walls responsible for Hc in the absence of the drive field H. The actual shape and frequency of the core current pulses appear to be immaterial as long as the condition J=J0 at H = 0 is fulfilled. The accurate measurements performed on the stress-free Co70.3Fe4.7Si15B10 and twisted Fe80B20 ribbons confirm the validity of the model. Some applications of the phenomenon are briefly discussed.Nedavno predloženi model za sniženje koercitivnog polja Hc i gubitaka energije u feromagnetskim trakama kojima teče istosmjerna struja Jd proširen je na izmjenične struje J. U slučaju izmjenične struje model predviđa linearno smanjenje Hc s amplitudom J(J0) te dostizanje Hc = 0 kod vrijednosti J0 koja je dostatna da oslobodi domenske zidove koji su odgovorni za Hc u odsustvu magnetizirajućeg polja H. Sam oblik i frekvencija J su nevažni dotle dok je J = J0 za H = 0 ispunjeno. Precizna mjerenja izvršena na nenapregnutoj Co70.3Fe4.7Si15B10 i tordiranoj Fe80B20 amorfnoj slitini potvrđuju valjanost modela. Ukratko su razmatrane neke primjene modela te posebno odsustva koercitivnog polja