Open Access
A lock-in amplifier for magnetic nanoparticle detection using GMI sensors
(IEEE, 2024-09-30) Algueta-Miguel, Jose M.; Beato López, Juan Jesús; López Martín, Antonio; Gómez Polo, Cristina; Ciencias; Zientziak; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Institute of Smart Cities - ISC
A digital lock-in amplifier (LIA) for contactless magnetic nanoparticle (MNP) detection using giant magnetoimpedance (GMI) sensors is presented. The proposed approach is based on the simultaneous detection of the second harmonic amplitude and phase. A Xilinx Artix-7 field-programmable gate array (FPGA) has been employed for efficiently implementing the phase-sensitive detection (PSD) and the subsequent digital processing. The analog GMI sensor interface has been designed for minimizing the dependence of the excitation current on the GMI sensor impedance, also enhancing the rejection of the parasitic second-order distortion produced by the setup. A subsampling process of the analog outputs has been applied, both increasing the effective resolution of the analog-to-digital converter (ADC) and facilitating signal recovery. The proposed system improves the MNP detection capability reported in previous works using the second harmonic amplitude. Moreover, a characterization of the phase response, which had not been previously studied in the literature, is also provided.
Open Access
Effect of Cu substitution on the magnetic and magnetic induction heating response of CdFe₂O₄ spinel ferrite
(Elsevier, 2020) Ghasemi, R.; Echeverría Morrás, Jesús; Pérez de Landazábal Berganzo, José Ignacio; Beato López, Juan Jesús; Naseri, M.; Gómez Polo, Cristina; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias
In this work, a comparative study of the effect of Cu on the structural, magnetic and magnetic induction heating response in CdFe2O4 spinel is presented. The ceramic nanoparticles (Cu1−xCdxFe2O4; 0 ≤ x ≤ 1) were synthesized by co-precipitation from Cu(II), Cd(II) and Fe(III) salts. The samples, characterized by X-ray diffractometry, display the characteristic spinel cubic structure (space group Fm3m) where CdO is detected as main secondary phase (≈ 16% weight for x = 1). A high degree of nanoparticle agglomeration is inferred from the Transmission Electron Microscopy (TEM) images, as a consequence of the employed synthesis procedure. Regarding the magnetic properties, superparamagnetic behavior at room temperature can be disregarded according to the low field magnetization response (ZFC-FC curves). For 0.4 ≤ x ≤ 0.8 ratios, the samples display maximum values in the magnetic moment that should be correlated to the cation distribution between the octahedral and tetrahedral sites. Maximum magnetization values lead to an enhancement in the magnetic induction heating response characterized by highest heating temperatures under the action of an ac magnetic field. In particular, maximum SAR values are estimated for x = 0.8 as a combined effect of high magnetic moment, low dc coercive field (high susceptibility). Although these Cu-Cd ferrite nanoparticles display moderate SAR values (around 0.7 W/g), the control of the maximum heating temperatures through the cation distribution (composition) provides promising properties to be used as nanosized heating elements (i.e. hyperthermia agents).
Open Access
Magnetically activated 3D printable polylactic acid/polycaprolactone/magnetite composites for magnetic induction heating generation
(Springer, 2023) Galarreta Rodríguez, Itziar; López Ortega, Alberto; Garayo Urabayen, Eneko; Beato López, Juan Jesús; La Roca, Paulo Matías; Sánchez-Alarcos Gómez, Vicente; Recarte Callado, Vicente; Gómez Polo, Cristina; Pérez de Landazábal Berganzo, José Ignacio; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Additive manufacturing technology has attracted the attention of industrial and technological sectors due to the versatility of the design and the easy manufacture of structural and functional elements based on composite materials. The embedding of magnetic nanoparticles in the polymeric matrix enables the development of an easy manufacturing process of low-cost magnetically active novel polymeric composites. In this work, we report a series of magnetic composites prepared by solution casting method combining 5 to 60 wt.% of 140 ± 50 nm commercial Fe3O4 nanoparticles, with a semi-crystalline, biocompatible, and biodegradable polymeric blend made of polylactic acid (PLA) and polycaprolactone (PCL). The composites were extruded, obtaining 1.5 ± 0.2 mm diameter continuous and flexible filaments for fused deposition modelling 3D printing. The chemical, magnetic, and calorimetric properties of the obtained filaments were investigated by differential scanning calorimetry, thermogravimetric analysis, magnetometry, and scanning electron microscopy. Furthermore, taking advantage of the magnetic character of the filaments, their capability to generate heat under the application of low-frequency alternating magnetic fields (magnetic induction heating) was analyzed. The obtained results expose the versatility of these easy manufacturing and low-cost filaments, where selecting a desired composition, the heating capacity can be properly adjusted for those applications where magnetic induction plays a key role (i.e., magnetic hyperthermia, drug release, heterogeneous catalysis, water electrolysis, gas capture, or materials synthesis).
Open Access
Tailoring the structural and magnetic properties of Co-Zn nanosized ferrites for hyperthermia applications
(Elsevier, 2018) Gómez Polo, Cristina; Recarte Callado, Vicente; Cervera Gabalda, Laura María; Beato López, Juan Jesús; López García, Javier; Rodríguez Velamazán, José Alberto; Ugarte Martínez, María Dolores; Mendonça, E. C.; Duque, J. G. S.; Zientziak; Estatistika, Informatika eta Matematika; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias; Estadística, Informática y Matemáticas; Gobierno de Navarra / Nafarroako Gobernua
A comparative study of the magnetic properties (magnetic moment, magnetocrystalline anisotropy) and hyperthermia response in Co-Zn spinel nanoparticles is presented. The CoxZn1-xFe2O4 nanoparticles (x = 1, 0.5, 0.4, 0.3, 0.2 and 0.1) were synthesized by co-precipitated method and the morphology and mean crystallite size (around 10 nm) of the nanoparticles were analysed by TEM Microscopy. Regarding the magnetic characterization (SQUID magnetometry), Co-Zn nanoparticles display at room temperature anhysteretic magnetization curves, characteristic of the superparamagnetic behavior. A decrease in the blocking temperature, T-B, with Zn content is experimentally detected that can be ascribed to the reduction in the mean nanoparticle size as x decreases. Furthermore, the reduction in the magnetocrystalline anisotropy with Zn inclusion is confirmed through the analysis of TB versus the mean volume of the nanoparticles and the law of approach to saturation. Maximum magnetization is achieved for x = 0.5 as a result of the cation distribution between octahedral and tetrahedral spinel sites, analysed by neutron diffraction studies. The occurrence of a canted spin arrangement (Yafet-Kittel angle) is introduced to properly fit the magnetic spinel structures. Finally, the heating capacity of these spinel ferrites is analyzed under ac magnetic field (magnetic hyperthermia). Maximum SAR (Specific Absorption Rate) values are achieved for x = 0.5 that should be correlated to the maximum magnetic moment of this composition.
Open Access
Contactless magnetic nanoparticle detection platform based on non-linear GMI effect
(Elsevier, 2021) Beato López, Juan Jesús; Algueta-Miguel, Jose M.; Gómez Polo, Cristina; Zientziak; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute for Advanced Materials and Mathematics - INAMAT2; Institute of Smart Cities - ISC; Ciencias; Ingeniería Eléctrica, Electrónica y de Comunicación
A detection platform based on non-linear Giant Magnetoimpedance Effect was analyzed for the design of a contactless and low-cost detector of magnetic nanoparticles. The sensor consists of two soft magnetic amorphous wires (Co66Fe2Si13B15Cr4, 1.5 cm in length) placed in parallel and connected electrically in series. Initially, a simple voltage divider was employed to characterize the variations of the first, V1fand second harmonic, V2f, voltages. Their response was analyzed under the effect of the remnant magnetic field generated by different amounts of Fe3O4 nanoparticles (mean diameter 140 nm) as a function of an external magnetic field, H. Due to the larger relative variations showed by V2f, the second harmonic was chosen for the final prototype development. An electronic interface was designed for both current excitation and V2f detection. The designed detection platform, characterized by high detection sensitivity, low-cost, portable, and reusable features, can be employed to efficiently detect magnetic nanoparticles.

Beato López, Juan Jesús

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