Origin of Stripe Domains in Ni–Fe Films

Abstract

Magnetic properties and domain structures in narrow NiFe stripes

Thick permalloy films for the imaging of spin texture dynamics in perpendicularly magnetized systems

“…In conclusion, we have demonstrated that microstructured disc elements fabricated out of thick Py films grown to achieve a weak PMA stabilize, as observed in a number of previous works [16][17][18][19][20][21], a perpendicularly magnetized configuration, composed of a circular magnetic domain at the center of the disc surrounded by ring shaped magnetic domains, the number of which is determined by the ratio between the diameter of the disc and the average width of the stripe domains [19]. Depending on the diameter of the disc structures, perpendicularly magnetized states ranging from an isolated magnetic skyrmion to more complex nπ states are stabilized.…”

“…where M s = 765.8 kA m −1 is the saturation magnetization obtained from superconducting quantum interference device magnetometry. The value of µ 0 M eff was determined from FMR This weak PMA is attributed to shape anisotropy effects caused by the columnar growth of the Py films [16][17][18]. The columnar growth of the Py films presented here was qualitatively verified by scanning electron microscopy imaging of the cross-section of the as-grown Py films, an example of which is shown in Fig.…”

“…The presence of such magnetic states in thick Py films has been known since more than 50 years [16][17][18][19][20][21], but, surprisingly, no experimental attempt to investigate the dynamical processes (such as e.g. the gyration dynamics of the magnetic skyrmions stabilized at the center of the disc structures) has been carried out.…”

Target domains in nanometric Permalloy disks with columnar structure

“…The patterned elements thickness is generally of a few tens of nanometers, with lateral size in the 100 to 1000 nm range. This type of films combining easy-plane anisotropy with a slight out-of-plane anisotropy component, tends to exhibit an homogeneous in-plane magnetization at wafer level below a critical thickness tc and a so-called stripe domain structure above tc [11][12][13][14][15][16][17]. The critical thickness normalized by the exchange length was shown to be a function of the film quality 3 factor = , where is the perpendicular anisotropy constant.…”

“…departing from Ni81Fe19 for NiFe alloys) [13][14][15], and/or to the columnar structure of sputtered samples [11,12], especially in samples deposited in poor vacuum in which impurities accumulate within the grain boundaries [11,12]. In some cases, the induced perpendicular has been shown to be non-uniform along the thickness of the film due to grain coarsening and evolution in the film texture [16].…”