Seminars and Events

Seminars and Events

Young Scientists Meetings at ICMM

Coordinadores: Iñigo Bretos y Lidia Martínez

 


09 March 2020, 12:00 h. Salón de Actos

High-Speed Bimodal AFM nanomechanical mapping of collagen self-assembly

Víctor García Gisbert
ICMM-CSIC


Collagen is the most abundant structural protein of the extracellular matrix. The assembly of collagen fibrils play relevant roles in a variety biological processes. The formation fibrils during the self-assembly process of collagen I have been studied by AFM [1,2]. Those studies lacked the time and mechanical properties resolution to clarify the mechanism of the earlier stages of collagen assembly and fibril structure formation. We have developed a high-speed bimodal AFM that combines the ms time resolution of high-speed AFM [3] with the nanomechanical force sensitivity of bimodal AFM [4,5]. High-speed bimodal AFM characterizes the earliest stages of the self-assembly of the collagen fibrils by proving time-resolved and high-spatial resolution maps of the evolution of the elasticity of the fibrils during the growth.

[1] F. Jiang, H. Hörber, J. Howard, D.J. Müller., J. Struct. Biol. 148, 268–278 (2004).
[2] D.R. Stamov, E. Stock, C.M. Franz, T. Jähnke, H. Haschke, Ultramicroscopy 149, 86–94 (2015).
[3] T. Ando. Nanotechnology 23, 062001 ( 2012)
[4] S. Benaglia, V.G. Gisbert, A.P. Perrino, C.A. Amo, R. Garcia, Nat. Protoc. 13, 2890 (2018)
[5] E.T. Herruzo, A.P. Perrino, R. Garcia, Nat. Commun. 5, 3126 (2014).


24 February 2020, 12:00 h. Salón de Actos

2D-based materials for bio-sensing and optolectronics

Sandra Cortijo Campos
ICMM-CSIC


Different approaches for 2D-based specific-sensors are being developed towards applications for detection of ultra-thin materials and health relevant molecules such as biomarkers. One approach is based on the covalent functionalization of graphene by adding carboxylic acid groups which allow successive binding with biologically active molecules for specific antigen sensing. We present a new method for in-situ specific functionalization of graphene that provides highly conductive cm-sized single-layer COOH-graphene. Anchoring of the biomolecules is demonstrated through fluorescence images of the marked antibody. We have also designed a new amplification platform based on silica membranes where graphene is the support of the molecules to be detected by interference enhanced Raman scattering (IERS). We present another selective bio-sensor based on the modifications in the photoluminescence characteristics of MoS2 single-layers grown by CVD that occurs when a mRNA probe, anchored to the MoS2 flakes, is bonded to its complementary mRNA. On the other hand, the synthesis of large area single-layer transition metal dichalcogenides (TMDC) by CVD is very relevant for the implementations in real devices of these extremely promising materials. Our main objective in this area is the controlled doping of 2D-TMDC with magnetic transition metals and with rare earths for applications in spintronics and optolectronics, for example for single photon emission and detection. In this context, we have designed and installed a low pressure CVD system that allows different approaches for 2D MoS2 growth as well as its doping.


24 February 2020, 12:30 h. Salón de Actos

Optoelectronics devices based on
two-dimensional materials

Dr. Riccardo Frisenda
ICMM-CSIC


Two-dimensional (2D) materials, which are based on layered van der Waals crystals, provide a unique opportunity for electronic and optoelectronic devices. In particular, semiconducting 2D materials, such as molybdenite or indium selenide, possess interesting properties that are related to their reduced dimensions. For example, the presence of sizeable and thickness-dependent bandgap and the strong light-matter interaction can be exploited for light‐emitting and light‐sensing purposes in nanoscale devices. Moreover, different 2D materials can be easily combined into van der Waals heterostructures, without the typical interfacial lattice-matching constraints encountered in epitaxial growth of conventional heterostructures. In this presentation I will discuss the fabrication and the properties of different devices based on 2D materials and their heterostructures.


14 January 2020, 12:00 h. Salón de Actos

Time-resolved measurements of domain wall velocity in amorphous magnetic microwires

Esther Calle Ramírez
Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC)


The dynamic process of nucleation, propagation and braking of a single domain wall (DW) has been systematically determined in a Fe-based magnetostrictive microwire under the action of an axial magnetic field. While in previous reports the Sixtus-Tonks experiments have provided partial information on the process (i.e., the average velocity), in the present study we report on the instantaneous processes involved in the propagation of the DW, as well as the transient process during the DW depinning. The experimental measurements were carried out using the spontaneous Matteucci effect induced during DW propagation due to the small helical magnetization component created during the fabrication process.


14 January 2020, 12:30 h. Salón de Actos

Magnetic materials with perpendicular magnetic anisotropy (PMA): Different easy ways to control them

Dr. David Navas Otero
Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC)


Since the middle of the 1970´s, when Iwasaki et al. proposed perpendicular magnetic recording (PMR) as an alternative to conventional longitudinal magnetic recording [1], thin films with perpendicular magnetic anisotropy (PMA) have been widely studied for recording media applications as well as for patterned magnetic media [2]. Magnetic films with PMA patterned into stripes and lines [3] have been also proposed for nanoscale spintronic devices such as those based on current-driven domain wall motion. Recently, the possibility to use ultrathin films with PMA has opened the path towards the development of skyrmionic devices [4]. Moreover, synthetic antiferromagnets, based on materials with PMA, have been also suggested for biologimedical applications [5].
In this seminar, we will discuss different alternatives to prepare and control nanostructured material with PMA, such as CoCrPt and CoFeB alloys, as well as the study of their related magnetic behaviours.

1. S. Iwasaki, and Y. Nakamura, IEEE Trans. Magn. 14, 436 (1978).
2. S.N. Piramanayagam and K. Srinivasan, J. Magn. Magn. Mater. 321, 485 (2009).
3. S. Emori et al., Nature Materials 12, 611 (2013).
4. A. Fert et al., Nanotechnology 8, 152 (2013).
5. T. Vemulkar et al., Applied Physics Letters 107, 012403 (2015).




   

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