Miguel Canhota, estudante de doutoramento do programa doutoral MAP-Fis no Departamento de Física e Astronomia (DFA) da FCUP, foi um dos 10 galardoados dos prémios para estudantes atribuídos este ano pela European Physical Society (EPS), através da sua divisão de Electrónica Quântica e Óptica - Quantum Electronics and Optics Division (QEOD) - e do Young Minds Action Committee.
Este prémio, o EPS-QEOD Travel Grant Student Award, destina-se a estudantes cuja contribuição científica em óptica e fotónica é considerada da mais alta qualidade, e inclui um diploma e apoio financeiro para a participação na conferência internacional Conference on Lasers and Electro-Optics – European Quantum Electronics Conference (CLEO/Europe-EQEC 2017). A conferência CLEO Europe tem lugar a cada dois anos, sendo o evento científico mais importante e de maiores dimensões em óptica, lasers e fotónica de toda a Europa. O prémio será entregue numa Sessão Plenária da CLEO, a ter lugar em Munique (Alemanha) no próximo dia 27 de Junho.
O trabalho de doutoramento do estudante Miguel Canhota está a ser desenvolvido no Grupo de Lasers Ultra-rápidos e Espectroscopias Magnetodinâmicas do IFIMUP-IN/DFA (Prof. Helder Crespo) em colaboração com a o Grupo de Física do Laser, Óptica Quântica e Óptica Não-linear da Universidade Complutense de Madrid (Prof. Rosa Weigand).
Na conferência CLEO, o estudante Miguel Canhota irá apresentar dois trabalhos (uma comunicação oral e um poster) totalmente realizados no laboratório de impulsos laser ultra-curtos Femtolab do IFIMUP-IN. Apesar das dificuldades de financiamento em ciência que se têm sentido em Portugal nos últimos anos, quer em projectos de investigação quer em bolsas de doutoramento, têm-se feito grandes esforços para manter este laboratório em operação, sendo que a manutenção e reparação de todo o equipamento avançado têm sido asseguradas na sua totalidade por membros do grupo de investigação. Apesar destas condições, o grupo mantém a sua motivação para a produção de ciência de qualidade e para a publicação em revistas científicas de referência, esforços que foram agora reconhecidos pela European Physical Society. No primeiro trabalho (comunicação oral) foi desenvolvido um novo método para a caracterização temporal de impulsos luminosos ultra-curtos no regime de poucos femtosegundos (1 femtosegundo = 0,000.000.000.000.001 segundos), capaz de medir impulsos com apenas um ciclo-óptico de duração e numa larga gama espectral, do infravermelho ao ultravioleta, o qual tem aplicações em várias áreas da ciência e tecnologia. O segundo trabalho (comunicação em poster) prende-se com o estudo e caracterização de um novo método para a produção de impulsos luminosos ultra-curtos de alta energia baseado em propagação não-linear em meios finos e transparentes, o qual poderá estar na base de novos sistemas para a geração de raios-X coerentes na gama dos atosegundos (1 atosegundo = 0,001 femtosegundos) e para a aceleração de partículas por laser. O grupo do Porto viu também aceites três outras comunicações orais na conferência CLEO, resultantes de trabalho desenvolvido em colaboração com as Universidades de Salamanca (Espanha), Lund (Suécia), e a spin-off tecnológica da Universidade do Porto, Sphere Ultrafast Photonics. A lista completa de laureados encontra-se neste link.
Dr. José Diogo Costa defended today his PhD Thesis
Dr. José Diogo Costa defended today his PhD Thesis on “Spin-transfer-torque nano-oscillators: fabrication, characterization and dynamics"Our warmest congratulations to José Diogo Costa and to his supervisors, Prof. João Oliveira Ventura and Dr. Ricardo Alexandre de Matos Antunes Ferreira In this thesis, magnetic dynamics were exploited for novel nanoelectronic devices. In particular, a cleanroom nanofabrication process was developed to successfully achieve nanosized radiofrequency emitters. These devices use the current-induced dynamics (through the spin transfer torque effect) in conjugation with the nanometric dimensions to operate. Their output power could be enhanced through the optimization of the insulating barrier thickness and several geometries (vortices, point-contacts and perpendicular polarizer) were built. Moreover, fundamental studies concerning the ultrafast magnetic and electric dynamics were also performed, pushing the field of spintronics to the THz range.
Terahertz dynamics of spins and charges in CoFe/Al2O3 multilayers, J. D. Costa, T. J. Huisman, R. V. Mikhaylovskiy, I. Razdolski, J. Ventura, J. M. Teixeira, D. S. Schmool, G. N. Kakazei, S. Cardoso, P. P. Freitas, Th. Rasing, and A. V. Kimel, Phys. Rev. B, 91, 104407 (2015). http://journals.aps.org/prb/abstract/10.1103/PhysRevB.91.104407
Impact of MgO thickness on the performance of spin transfer torque nano-oscillators, J. D. Costa, S. Serrano-Guisan, J. Borme, F. L. Deepak, M. Tarequzzaman, E. Paz, J.Ventura, R. Ferreira and P.P. Freitas, IEEE Trans. Magn., 51, 11 (2015). http://ieeexplore.ieee.org/document/7117429/
Femtosecond control of electric currents in metallic ferromagnetic heterostructures, T. J. Huisman, R. V. Mikhaylovskiy, J. D. Costa, F. Freimuth, E. Paz, J. Ventura, P. P. Freitas, S. Blügel, Y. Mokrousov, Th. Rasing, and A. V. Kimel, Nat. Nanotech., 11, 455-459 (2016). http://www.nature.com/nnano/journal/v11/n5/full/nnano.2015.331.html
Dr. Mariana Proença was one of the Outstanding Reviewers of Nanotechnology in 2016
Dr. Gonçalo Oliveira defended today his PhD Thesis
Dr. Gonçalo Oliveira defended today his PhD Thesis on “Local probing spinel and perovskites complex magnetic systems”. Our warmest congratulations to Dr. Gonçalo Oliveira and to his supervisors, Prof. João Pedro Araújo and Dr. Armandina Lopes. The work focused on potential multifunctional bulk materials, aiming to enhance their multiferroic properties and to contribute to the fundamental understanding of its magnetoelectric coupling (its origin and how to enhance it). Here, the combination of local scale information (analysis of the magnetic hyperfine field, electric field gradient and local structural information) with macroscopic data allowed to obtain local signatures of the magnetoelectric effect and in this way better understand from a fundamental point of view, the origin of the macroscopic properties they exhibit.
G.N.P.Oliveira,A.M.Pereira,A.M.L.Lopes,J.S.Amaral,A.M.dosSantos,Y.Ren, T.M. Mendonça, C.T. Sousa, V.S. Amaral, J.G. Correia, and J.P. Araújo, Dynamic off-centering of Cr3+ ions and short-range magneto-electric clusters in CdCr2S4, Phys. Rev. B 86, 224418 (2012). https://doi.org/10.1103/PhysRevB.86.224418
G.N.P. Oliveira, R. Teixeira, T.M. Mendonça, M.R. Silva, J.G. Correia, A.M.L. Lopes, and J.P. Araújo, Local symmetry lowering in CdMn2O4 spinel, J. Appl. Phys. 116, 223907 (2014). https://doi.org/10.1063/1.4903949
Membros do IFIMUP vencem Pitch Day da Escola de Startups do UPTEC
O projeto empresarial WEStoreOnTEX, venceu o Pitch Day, Escola de Startups do UPTEC.
A equipa é constituída por Clara Pereira (Investigadora REQUIMTE/LAQV no DQB), André Pereira (Docente no DFA e Investigador IFIMUP-IN) e Rui Costa (Mestre em Engenharia Física da FCUP).
O evento Pitch Day decorreu no passado dia 2 de fevereiro e assinalou o encerramento da 8ª edição da Escola
de Startups do Parque de Ciência e Tecnologia da Universidade do Porto, que é um programa de mentoring e formação de 3 meses que acelera ideias de negócio nas áreas tecnológica, científica e criativa. Neste evento, 17 projetos empresariais foram apresentados pelos seus responsáveis em apenas 3 minutos.
A WEStoreOnTEX está a desenvolver têxteis e acessórios flexíveis que armazenam energia para alimentar dispositivos eletrónicos e sensores integrados na própria roupa. O mercado-alvo é o mercado do desporto e bem-estar.
André Pereira, Clara Pereira e Rui Costa (da esq. para dir.), fundadores da WEStoreOnTEX
of the president of the Portuguese Republic, Marcelo Rebelo de Sousa, was performed by researchers from IFIMUP-IN
The president of the Portuguese Republic, Prof. Marcelo Rebelo de Sousa, visited the Faculty of Sciences of the University of Porto to celebrate its 105th Anniversary. He visited several departments such as the Department of Physics and Astronomy, where researchers from the FEMTOLAB, one of the research Units of IFIMUP-IN, performed the hologram of the president (a three-dimensional laser picture). This technique was already used in 2003 to obtain the hologram of the president of the Republic Jorge Sampaio.
More details about the president visit as well as the hologram techniques can
be found out on the online video where Prof. Hélder Crespo,
a member of IFIMUP-IN, was interviewed.
18.11.2016 This is my text .
Researchers from IFIMUP-IN published a scientific article on Triboelectric Nanogenerators in Nano Energy
A recent study on the development of an innovative type of triboelectric nanogenerators (TENGs) to effectively harvest water energy led by researchers from the Institute of Physics of Materials of the University of Porto (IFIMUP), located in the Faculty of Sciences of University of Porto and a member of the National Associate Laboratory Institute of Nanoscience and Nanotechnology (IN), was published on the prestigious Nano Energy journal (http://authors.elsevier.com/a/1TyTt7soS7iZxq).
Triboelectric nanogenerators are a new promising energy harvesting technology that has a simple working mechanism, produces high output power and has the ability of harvesting energy from a wide range of sources and under various conditions. In this research, the authors of the study developed a rotary triboelectric nanogenerator designed to harvest small-scale water energy in our normal living environment, using polytetrafluoroethylene (PTFE) and Nylon 6.6 as the pair of triboelectric materials. The operation mechanism of the fabricated rotary TENG is a hybridization of the contact and sliding modes by using the triboelectrification and electrostatic induction effects.
The optimization of the developed setup for the effective generation of electricity showed that the best configuration consists in a triboelectric structure with four Nylon and one PTFE plate for a water flow of 44 L/min. With this configuration, the rotary TENG delivers a mean voltage value of ∼102.2 V, a short-circuit current density ∼120 mA/m2 and a maximum power density of ∼6.1 W/m2. With this device, it was possible to light more than 50 serial-connected light emitting diodes, fully charge a 1.0 μF capacitor with 15.2 V in just 65 s and feed a commercial temperature and humidity sensor.
With small changes in the structure of the rotary TENG, it is possible to place the device in any environment (water pipelines, taps of housing, etc) because it was built to function as watertight. This guarantees a longer durability of the material because there is less wear and no influence on the triboelectrification effect by other external agents. The developed device can also be redesigned to work for very small water flows.
The results obtained in this research open the prospect for the future development and optimization of these devices, along with the possibility to apply them as autonomous sensors to monitor water supply systems that can work and send data using the energy produced by water movement in plumbing. Additionally, the rotary TENG can be miniaturized to apply this technology in the microfluidics field.
The authors acknowledge funding from FEDER and ON2 through projects Norte-070124-FEDER-000070, FSE/POPH and PTDC/CTM-NAN/3146/2014 and from FCT through the Associated Laboratory - IN.
18.11.2016 This is my text .
IFIMUP-IN researchers publish scientific article about Magnetically Activated Thermal Switches in Nano Energy journal
A recent study on the development of an innovative magnetically activated thermal switch led by researchers from the Institute of Physics of Materials of the University of Porto (IFIMUP), located in the Faculty of Sciences of University of Porto and a member of the National Associate Laboratory Institute of Nanoscience and Nanotechnology (IN), was published on the prestigious Nano Energy journal (http://dx.doi.org/10.1016/j.nanoen.2016.11.031).
With the exponential rise of power dissipation in electric devices such as integrated circuits or micro/nano electro mechanical systems (MEMS/NEMS), new thermal management solutions are in high demand. Thermal switches, being devices capable of controlling the temperature flow between two surfaces, are one of the solutions capable of effectively tackling this problem.
In this research, the authors present an innovative magnetically actuated thermal switch based on nanofluids capable of controlling both the magnitude and direction of the heat flux. This device takes advantage of the thermal conductivity increase in magnetic nanofluids when submitted to an applied magnetic field parallel to the temperature gradient. The increase of thermal conductivity and the movement of the nanofluid inside the thermal switch prototype reduces the temperature gradient across the device.
The magnetically actuated thermal switch comprises of a thermally insulator body with two thermally conductive windows at the top and bottom. This forms a closed container where the magnetic nanofluid is confined. The device has two operating states (ON and OFF) depending whether heat is being transported between the two windows or not. In the OFF state no magnetic field is applied and the MNF remains in the bottom of the insulator cage (heat source). When an external magnetic field is applied (ON state), the MNF moves from the bottom of the insulator cage to the top surface, carrying the heat absorbed from the heat source and releasing it at the heat sink.
The researchers built two prototypes with different heights between the top and bottom (3 and 1 cm). Both devices were tested for a range of magnetic field frequencies between 0.01 and 30 Hz with an initial temperature gradient of approximately 35 ºC. The experimental results showed a clear dependence between operation performance and the thermal switch size. While the larger prototype showed a decrement in heat transport for frequencies above 10 Hz, the smaller one showed no operational frequency limitations up to 30 Hz. For the maximum temperature gradient variation it was calculated that the thermal conductivity variation between the ON and OFF stages was of 260%. Finally, the researchers tested the applicability of magnetically actuated thermal switch in the thermal management of a LED and demonstrated the possibility to enhance heat removal and control the LED maximum temperature.
With a novel operating principle, simple design, wide range of operating temperatures and the potential for downsize, it is expected that the presented magnetically actuated thermal switch can be adapted to numerous applications of thermal management such as light sources, electronic devices, bio-devices, thermal storage systems or magnetocaloric refrigerators.
The authors acknowledge funding from FEDER and ON2 through projects Norte-070124-FEDER-000070, FSE/POPH, EXPL/EMS-ENE/2315/2013 and PTDC/CTM-NAN/3146/2014 and from FCT through the Associated Laboratory - IN.