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We demonstrate a high yield production scheme to fabricate sub-5 nm co-planar metal-insulator-metal junctions. This involves determining the relationship between the actual gap between the metallic junctions for a given designed gap, and the use of weak developers with ultrasonic agitation to process the exposed resist. This results in an improved process to achieve narrow inter-electrode gaps. The gaps were imaged using an AFM equipped with a carbon nanotube tip to achieve a high degree of accuracy in measurement. The smallest gap unambiguously measured was ∼2 nm. Gaps with 5 nm spacing were produced with a very high yield of about 75% for a designed inter-electrode distance of 0 nm. The leakage resistance of the gaps was found to be of the order of 10 12 . The entire junction structure was designed to be co-planar to better than 1 nm over 1 µm 2 .

Influence of single-ion anisotropy fluctuations on temperature-driven reorientation transition in two-dimensional ferromagnets Appl.A systematic study of micromagnetic configurations in thin equilateral triangular prisms as a function of lateral size and thickness is reported. The resulting map of a micromagnetic ground state is presented in the form of a micromagnetic phase diagram with two regions corresponding to buckle and Y-state configurations. These configurations led to the formation of a configurational anisotropy field, an ab initio calculation of which is presented and the results are compared with experiment. The calculated six-fold symmetric anisotropy field agreed well with experiment but was found to depend on the applied field in phase and magnitude. The anisotropy field dependence on the triangular nanostructure edge roughness was also investigated and related to the stability of the micromagnetic phases.

A hybrid magneto-optical magnetometer and optical microscope has been designed and constructed for probing the magnetic properties of submicron nanomagnets. 10-nm-thick square nanomagnets have been fabricated individually and in small arrays from Ni80Fe14Mo5 (“supermalloy”) by electron-beam lithography. Hysteresis loops with a good signal-to-noise ratio have been obtained from individual nanomagnets as small as 400 nm and from (5 μm)2 arrays of nanomagnets ranging in size from 500 to 75 nm.

We have investigated experimentally the influence of the geometric shape of deep sub-micron nanomagnets on their magnetic properties. We have used high-resolution electron beam lithography to make arrays of nanomagnets in the size range 40-500 nm which had rectangular, triangular, square and pentagonal geometries, corresponding, respectively, to rotational symmetries of order 2, 3, 4 and 5. The parent material was Supermalloy (Ni 80Fe14Mo5). We find that an enormously wide range of magnetic properties, including some not found in conventional unstructured materials, can be obtained by using different geometries. We demonstrate that this is because the geometric shape imposes a strong anisotropy field of related symmetry order on the nanomagnet via a recently discovered phenomenon called configurational anisotropy. We show that the coercive field and remanence of these structures is determined directly by this anisotropy.