Permalloy films

Fig. 1. The effect of (------) coercive force, ( ) lesistivity, and ([[aitl]]) magnetoiesistance coefficient foi Permalloy films (a) at a constant argon...

Wirth, S. von Molnar, S. Magnetic interactions in nanometer-scale particle arrays grown onto permalloy films. J. Appl. Phys. 87, 7010-7012 (2000). 

Equation 98 is known as the Bloch Tm law. It is in good agreement with experiment at very low temperatures other phenomena begin to appear at somewhat higher temperatures. An interesting phenomenon that demonstrates the existence of spin waves is the spin wave resonance spectrum recently observed in Permalloy films (554,612). 

Electroplated permalloy films for use as thin-film heads are based on the technology of magnetic wire memory developed in the 1950s. Ever since IBM applied the... 

Hoffmann H (1964) Quantitative calculation of magnetic ripple of uniaxial thin permalloy films. J Appl Phys 35 1790-1798... 

With regard to magnetic domains, other studies have been devoted to the dynamic properties. Cuomo et al. (1974) showed that bubbles can reach a mobility and velocity higher than 1000 cm/s. Miyama et al. (1978, 1980) studied the effects of applied driving fields, of the temperature and of a permalloy film coating. They noticed a wall velocity as high as 15 000 cm/s for samples with high He- Their sputtered films had an orthorhombic anisotropy. They found a non-... 

Miyama et al. (1978) and Matsushita et al. (1978) have reported numerous magnetic data for GdCoAu films prepared by rf sputtering and coated with a permalloy (NiFe) film. Near Tpomp (285 K) they determined the dependence of Hp. Miyama et al. (1978) studied the dependence of the domain wall velocity on the presence of an overlayered permalloy film, the temperature and the drive field. They measured wall velocities up to 35 000 cm s and showed that the saturation of the wall velocity is suppressed by the permalloy overlay. Matsushita et al. (1978) showed that Ta,mp is lowered by about 5 K by coating of a permalloy film. They also found numerous domain patterns for different magnetized states. 

The beneficial additive effect on stress evolution during electrodeposition is shown in Fig. 16. In (A), from in situ measurements, one can see that for Permalloy films of 100 nm thickness, the significant stress reduction in deposit is achieved if saccharin (stress reduction 50%) or 1-Methionine (stress reduction 85%) is used as additives in plating solution. The effect of saccharine concentration on stress in electrode-posited CoNiFe films is shown in Fig. 16(B). These data suggest that stress reduction is decreasing towards asymptotic value for increasing saccharin content in the solution. 

Fig. 16. (A) In situ stress measurements for Permalloy films as a function their thick-...

Exposure of freshly deposited permalloy films to the atmosphere or oxidation in pure O2 up to 250°C results in surface segregation and preferential oxidation of Fe to Fe203 [144-146], However, anodically formed films are enriched in Ni and consist of an inner layer of NiO and an outer layer of mixed nickel and iron hydroxides [147,148]. The more reactive element Fe oxidizes first and is enriched at the surface during atmospheric oxidation but dissolves into solution during anodic oxidation. 

The method of deposition has been reported to have a large influence on the corrosion properties of permalloy [149-151]. In particular, plated permalloy films have been found to be more susceptible to corrosion than either bulk material or vacuum-deposited films of nominally the same composition. For instance, sputter-deposited permalloy was found to passivate in pH 2 solutions, but plated films did not [150]. Another study in neutral chloride solutions showed that plated permalloy had a lower pitting potential than bulk permalloy [151]. These reports suggested that plated films either have regions locally enriched in Fe or have a crystallographic orientation that is more susceptible to attack. However, little supporting evidence was provided. 

An explanation for the enhanced corrosion susceptibility of plated permalloy films was offered in a study that examined the walls of pits in thin-film samples using Auger electron spectroscopy [149]. The pit walls showed a large enhancement of... 

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