5 documents found, page 1 of 1
The ferromagnetic resonance (FMR) of SrZ hexaferrite (Sr3Co2Fe24O41), and the t...
Pullar, Robert C.; Galizia, Pietro; Migliano, Antonio C. C.; Amaral, João S.; Galassi, Carmen; Carvalho, Francisco E.The hexagonal Z-type ferrite Sr3Co2Fe24O41 (SrZ) was first synthesised in 2001 and reported as being a room temperature multiferroic material in 2010, with subsequent investigations into its multiferroic properties, but little into high frequency and microwave properties, and ferromagnetic resonance frequency (FMR), which determines its ability as an electromagnetic (EM) absorber and radar absorbing (RAM) steal...
Chemical strategies for dendritic magneto-plasmonic nanostructures applied to s...
Fernandes, Tiago; Nogueira, Helena I. S.; Amorim, Carlos O.; Amaral, João S.; Daniel-da-Silva, Ana L.; Trindade, TitoChemical analyses in the field using surface-enhanced Raman scattering (SERS) protocols are expected to be part of several analytical procedures applied to water quality monitoring. To date, these endeavors have been supported by developments in SERS substrate nanofabrication, instrumentation portability, and the internet of things. Here, we report distinct chemical strategies for preparing magneto-plasmonic (F...
Direct measurement and imaging of magnetocaloric effect inhomogeneities at the ...
Pereira, Maria J.; Santos, Tiago; Correia, R.; Amaral, João S.; Amaral, Vitor S.; Fabbrici, Simone; Albertini, FrancaTo study the MCE at the microscale with infrared thermography, a bulk Ni44Co6Mn30Ga20 sample was investigated. Direct measurements of the MCE were performed for temperatures around the reverse and direct martensitic transformation, by applying and removing a ~1.2 T magnetic field to the sample and recording the changes in its surface temperature with an IR camera. This was done for different sample temperatures...
Synthesis and characterisation of lead free BaFe12O19 –(K0.5Na0.5)NbO3 magnetoe...
Medeiros, Marco S. A.; Coondoo, Indrani; Oliveira, Filipe J. S.; Kholkin, Andrei L.; Amaral, João S.; Pullar, Robert C.Polycrystalline lead-free (1-x)BaFe12O19–x(K0.5Na0.5)NbO3 magnetoelectric ceramic composites (x = 10, 20 and 30 wt%) were fabricated for the first time, comparing various synthesis techniques, namely solid state reaction, sol-gel, co-precipitation and citrate combustion methods for the synthesis of the ferrite phase. As well as the four synthesis routes, comparisons were made between uniaxial pressing and cold ...
Synthesis of red mud derived M-type barium hexaferrites with tuneable coercivity
Carvalheiras, João; Novais, Rui M.; Mohseni, Farzin; Amaral, João S.; Seabra, Maria P.; Labrincha, João A.; Pullar, Robert C.Hexagonal ferrites can be employed in a multitude of applications, the most common hexaferrites are the M ferrites such as BaFe12O19 (barium hexaferrite, BaM). It is known that if Fe3+ is substituted with a combination of Ti4+/Co2+ the coercivity of BaM can be reduced to produce soft M ferrites with easily switchable magnetisation. They can be utilised as powders, films or bulk ceramics, and can be manufactured...