MOKE studies of patterned magnetic nanostructures for advanced storage applications
Keywords: magnetic storage, optical instrumentation, instrumentation, characterisation.
The magneto-optical Kerr effect (MOKE) is a powerful tool that is used to characterise magnetic materials for a variety of applications, in particular novel magnetic data storage media. The MOKE signal is characterised by the rotation in the plane of polarisation of linearly polarised light upon interaction with a magnetic material. In the case where the magnetisation of the material is perpendicular to its plane then we have the polar MOKE configuration, and the sign and magnitude of the rotation, which is generally very small, is proportional to the magnetisation and its direction. By measuring the MOKE signal in the presence of a variable external field, valuable information about the magnetic properties of the media may be ascertained, such as the coercivity and remanent magnetisation. However, in the case of nanostructured magnetic media, such as that proposed for use in future ultra-high density magnetic hard disk drives, studies have shown that the MOKE signal behaves differently in the regime where the size of the nanostructures is much less than the wavelength of light used.Project
The objective of this project is to build a MOKE system that will allow the investigation of the physical origins of the variation in MOKE signal observed in the exciting regime where the size of the magnetic nanostructures are much less than the wavelength of light. In particular, the design of this novel instrument will focus on being able to characterise magnetic nanostructures at a variable field angle as well as different wavelengths of illumination, this will allow us to ascertain more of an understanding of the interactions of light with magnetic nanostructures. The project will involve the development of instrumentation as well as the nanoscale patterning of magnetic materials for data storage applications. The project will enable the development of skills in designing and building optical and electronic instrumentation, as well as the opportunity to develop essential skills in nanofabrication.
The NEST Group
The Nano Engineering & Storage Technology (NEST) group is housed in an integrated suite of staff offices, general-purpose laboratory space and class 100/1000 cleanrooms. The group is a founder member of the Manchester Centre for Mesoscience and Nanotechnology (CMN), which is based in the group?s laboratories and contains state of the art lithography tools for the fabrication and visualisation of nanoscale structures. The group also has facilities for characterising magnetic media including a purpose built alternating gradient field magnetometer and an ADE Technologies vector vibrating sample magnetometer.