Micromagnetism and magnetization reversal of embedded ferromagnetic elements

Abstract

A unique type of ferromagnetic microelement is explored. Unlike conventional ferromagnetic elements, the entities studied here are not separated topographically from each other, but embedded into a surrounding, continuous film. Fabrication of such elements is achieved by local irradiation of antiferromagnetically coupled Fe/ Cr/ Fe trilayers with 30 keV Ga + ions, which cause a local destruction of the Cr interlayer in these systems. As a result, a transition to ferromagnetic properties is induced within micron-sized irradiated areas, which act as ferromagnetic elements. Since the surrounding area of these elements consists of magnetic material, i.e., two Fe layers which are still antiferromagnetically coupled, interesting coupling phenomena in lateral direction can be observed. In particular, the magnetic configuration within such systems leads to the formation of complex domain walls at the boundary between irradiated and nonirradiated areas exhibiting different types of fine structure. In addition, it is found that the capability of storing information in the form of magnetic single domain states in remanence depends on the geometry of the patterned elements. The fabrication method presented here is an efficient way to create magnetic model systems on the micron scale of different geometries and sizes for comparative studies of micromagnetics and magnetization reversal processes. E IEC = − J 1 cos͑␣͒ − J 2 cos 2 ͑␣͒, ͑1͒where J 1 and J 2 are the so-called "bilinear" and "biquadratic" coupling constants, ␣ denotes the angle between the PHYSICAL REVIEW B 74, 184405 ͑2006͒

Ion beam induced modification of exchange interaction and spin–orbit coupling in the Co2FeSi Heusler compound

“…[19,20,21] Moreover, it was demonstrated that such modifications can be performed with high spatial resolution, making ion irradiation an attractive patterning tool in view of technological applications. [12,13,17,18,21,22] In this work we demonstrate that the magnetic and, in particular, the magneto-optical properties of CFS Heusler alloys can also be modified by means of keV ion irradiation.…”

Magnetic patterning by means of ion irradiation and implantation

“…Up to now only two different systems are investigated, i.e., fully epitaxial Fe/Cr/Fe [54][55][56][57][58][59] and polycrystalline Ni 81 Fe 19 /Ru/Co 90 Fe 10 [60,61] sandwich structures. In both cases the coupling type between the ferromagnetic films, i.e., ferromagnetic or antiferromagnetic, oscillates as a function of interlayer thickness.…”

Interlayer exchange coupling of Fe/Cr/Fe thin films on rippled substrates

“…Using recent ion irradiation techniques to modify the interfaces after deposition the IEC can be tuned as well. 14,15 The first calculations concerning magnetostatic coupling arising from dipolar interactions were done by Néel in 1962. 16 This so-called Néel coupling deals with two separated semi-infinite ferromagnetic layers with in-plane magnetization and sinusoidally modulated surfaces and aligns both magnetizations parallel to each other, in case of conformal interface modulation at all interfaces of the trilayer stack.…”