Self-organized Fe nanostructures on W(110)

Reversible temperature-driven domain transition in bistable Fe magnetic nanostrips grown on Ru(0001)

“…By itself, this result is also expected: this type of flux-closure diamond multi-domain state can be seen in many other types of magnetic structures. 7,8,11,23,24 The interesting aspect of this system is that, unlike the cited previous studies, [7][8][9]11,12,24 we find that the transitions between these two states are reliably reversible under temperature cycling, and that the critical transition temperatures of individual nanostrips depend on their width. Indeed, we see that narrow nanostrips remain in a single-domain state up to their Curie temperature (T c ).…”

“…Next we address crystalline and geometric structure of the nanostrips. Fe grown on Ru(0001) surfaces under ultrahigh vacuum conditions is known to form bcc(110) islands in Kurdjumov-Sachs epitaxial orientation, 29 where the bcc [1][2][3][4][5][6][7][8][9][10][11] axis is parallel to the hcp [11][12][13][14][15][16][17][18][19][20] direction. In this epitaxial relationship, two bcc coincidences are possible for each closepacked direction of the underlying hcp lattice, oriented at +/-5° of the three equivalent [11][12][13][14][15][16][17][18][19][20] directions.…”

“…6,7 Many basic studies have focused on the occurrence of magnetic domain patterns as a function of particle geometry. [7][8][9][10][11] Temperature-controlled single-to multi-domain structure transitions remain less well explored; prior work on temperature dependent magnetic phenomena in small elements includes thermally induced fluctuations such as magnetic bistability of Co nanodots switching from single-domain to vortex states 12 and superparamagnetic properties of small elements more generally. 13 Interest in thermally activated magnetic transitions is driven by applications in memory and logic devices, 3,5 where some technologies depend on suppression of thermal effects (non-volatility of memory, etc.…”

Magnetic imaging with spin-polarized low-energy electron microscopy

“…Reduction of surface anisotropy does not appear to be a key driving force in the observed SRT. Rather, dipolar forces associated with the shapes of the voids that form when the film starts to dewet appear to initiate the rotation of magnetization while annealing, and ultimately the shape anisotropy of the islands determines the final easy axis of magnetization, as pointed out in other work [84].…”

“…For this type of problem, SPLEEM is ideally suited to obtain spatially resolved magnetic information in real time, during morphological changes that occur while annealing. For the Fe/W(110) system, SPLEEM measurements added new insights into the origin of this SRT [74,84].…”