Speaker
Dr.
Miriam Jaafar
(Instituto de Ciencia de Materiales de Madrid)
Description
Despite decades of advances in magnetic imaging, obtaining direct, quantitative information with high spatial resolution remains an outstanding challenge. The imaging technique most widely used for local characterization of magnetic nanostructures is the Magnetic Force Microscope (MFM), which is indeed a very active topic of investigation. Advantages of MFM include relatively high spatial resolution, simplicity in operation as well as sample preparation, and the capability to applied in situ magnetic fields to study magnetization process [1, 2]. Recently we have also demonstrate the possibility of operate in different environments including liquid media that allow us to investigate biological samples [3].
In the present work we try to approach some of the challenges of MFM, spatial resolution, sensitivity and quantitative measurements, by following different routes.
One route is the development of high-performance MFM probes with sub-10 nm (sub-25 nm) topographic (magnetic) lateral resolution by following different easy and quick low-cost approaches. This allows one to not only customize the tip stray field, avoiding tip-induced changes in the sample magnetization, but also to optimize MFM imaging in vacuum (or liquid media) by choosing tips mounted on hard (or soft) cantilevers, a technology that is currently not available on the market [4]. In Figure 1 we show an example of the advantages of tune the mechanical properties of the cantilever. We compare the MFM images of a reference sample (a commercial high disk) acquired with a commercial MFM tip (Figure 1 a and b) and a custom-made probe (Figure 1 c and d) at ambient conditions and in liquid environment. It is well known that due to the viscosity of the liquid media there is a decrease in the quality factor of the cantilever and, for that reason, an increase of the noise in the MFM images. Using specific customized MFM probes we can enhance the signal in about a factor of 10 and improve significatively the quality of the images. Moreover, with this customized MFM probes we can obtain MFM images of biological materials in physiological conditions. In figure 2 we present the topography and the magnetic signal of magnetotactic bacteria Magnetospirillum gryphiswaldense [5] acquired with custom made MFM tips. Furthermore, the idea of explore new MFM probe architectures [6] allow us to focus some of the challenges of the technique as the lack of quantitative information. In that sense, alternative advanced methods as measuring energy dissipation with MFM is of great interest not only for nanomechanics but also to understand important energy transformation and loss mechanisms that determine the efficiency of energy of data storage device [7].
Acknowledgments
We acknowledge the support from the Spanish Ministerio de Economia y Competitividad (MINECO) under projects no. MAT2013-48054-C2-1-R, Consolider CSD2010-00024, MAT2015-73775-JIN and MAT2016-76824-C3-1-R.
References
[1] M. Jaafar, L. Serrano-Ramón, O. Iglesias-Freire, A. Fernández-Pacheco, M.R. Ibarra, J.M. De Teresa, A. Asenjo, Nan. Res.Lett 6, 1 (2011)
[2] E. Berganza, C. Bran, M. Jaafar, M. Vázquez, A. Asenjo, Sci. Rep. 6, 29702 (2016)
[3]P. Ares, M. Jaafar, A. Gil, J. Gómez –Herrero, A. Asenjo, Small, 11, 4731–4736 (2015)
[4] O. Iglesias – Freire, M. Jaafar, E. Berganz, A. Asenjo, Beilstein J. Nanotechnol. 7, 1068-1074 (2016)
[5] A. M. Huízar-Félix, D. Muñoz, I. Orue, C. Magen, A. Ibarra, M. Barandiarán, A. Muela, M.L. Fernandez- Gubieda, Appl. Phys. Lett., 108, 6, 10.1063, (2016)
[6] H. Campanella, M. Jaafar,J. Llobet, J. Esteve, M. Vázquez, A. Asenjo, R. P. del Real and J. A. Plaza, Nanotechnology, 22, 505301(2011)
[7] M. Jaafar, O. Iglesias- Freire, P. García- Mochales, J.J. Saénz, A. Asenjo, Nanoscale 8, 16989-16994 (2016)
Primary author
Dr.
Miriam Jaafar
(Instituto de Ciencia de Materiales de Madrid)
