Material synthesis using femtosecond pulsed laser deposition (fs-PLD) in vacuum is an important application because an interesting by-product of the process is the automatic generation of nanometer scale particles during ablation. The nanoparticle-assembled films show a structure with agglomerates of NPs, each one formed by closely connected NPs with a significant shape and orientation anisotropy and negligible coalescence, even at high NP volume fractions, though the precise nature of the interface remains uncertain, and an exchange interaction is active among the nearest NPs. The as-deposited monocomponent (Ni, Fe) and bicomponent (CoCu, FeAg) magnetic films present a high in-plane remanence ratio, relatively low values of the saturation and coercive fields and a steep slope near coercivity. Furthermore, the exchange interaction between hard magnetic nanoparticles (Terfenol-D) and soft magnetic nanoparticles (Iron) is active in the fs-PLD film, giving a cumulative magnetic response resulting from an average of the properties of the two component phase (exchange-spring magnets). In prospective the striking and intriguing properties of these nanogranular films appear very promising for potential application as permanent magnets and in data storage technology. Finally, giant magnetoresistance effect in films of magnetic nanoparticles uniformly mixed with non-magnetic metallic nanoparticles produced by uPLD, was investigated. As-deposited Co-Cu and Fe-Ag films in a moderate volume fraction range of magnetic component (15 – 25 %) present detectable values of this magnetoresistive effect, although the average size of the particles is higher than in typical nanogranular materials for magnetoresistive applications. Moreover, the magnetoresitive response at room temperature is a linear function of field that does not saturate up to external magnetizing field (at least up to 5 T) very higher than the value required for the saturation of the macroscopic magnetization. In prospective, by optimizing the production parameters, these nanogranular films appear very promising for potential applications in room-temperature magnetic sensor technology.
The Magnetic and Magneto-transport Properties of Nanogranular Films Produced by Ultrashort Pulsed Laser Deposition / Iannotti, Vincenzo; Ausanio, Giovanni; C., Campana; Amoruso, Salvatore; L., Lanotte. - (2008). (Intervento presentato al convegno Taiwan-Italy Workshop on Nanoelectronics/Nanomagnetics tenutosi a National Cheng Kung University, Tainan (Taiwan) nel 20-21 October 2008).
The Magnetic and Magneto-transport Properties of Nanogranular Films Produced by Ultrashort Pulsed Laser Deposition
IANNOTTI, VINCENZO;AUSANIO, GIOVANNI;AMORUSO, SALVATORE;
2008
Abstract
Material synthesis using femtosecond pulsed laser deposition (fs-PLD) in vacuum is an important application because an interesting by-product of the process is the automatic generation of nanometer scale particles during ablation. The nanoparticle-assembled films show a structure with agglomerates of NPs, each one formed by closely connected NPs with a significant shape and orientation anisotropy and negligible coalescence, even at high NP volume fractions, though the precise nature of the interface remains uncertain, and an exchange interaction is active among the nearest NPs. The as-deposited monocomponent (Ni, Fe) and bicomponent (CoCu, FeAg) magnetic films present a high in-plane remanence ratio, relatively low values of the saturation and coercive fields and a steep slope near coercivity. Furthermore, the exchange interaction between hard magnetic nanoparticles (Terfenol-D) and soft magnetic nanoparticles (Iron) is active in the fs-PLD film, giving a cumulative magnetic response resulting from an average of the properties of the two component phase (exchange-spring magnets). In prospective the striking and intriguing properties of these nanogranular films appear very promising for potential application as permanent magnets and in data storage technology. Finally, giant magnetoresistance effect in films of magnetic nanoparticles uniformly mixed with non-magnetic metallic nanoparticles produced by uPLD, was investigated. As-deposited Co-Cu and Fe-Ag films in a moderate volume fraction range of magnetic component (15 – 25 %) present detectable values of this magnetoresistive effect, although the average size of the particles is higher than in typical nanogranular materials for magnetoresistive applications. Moreover, the magnetoresitive response at room temperature is a linear function of field that does not saturate up to external magnetizing field (at least up to 5 T) very higher than the value required for the saturation of the macroscopic magnetization. In prospective, by optimizing the production parameters, these nanogranular films appear very promising for potential applications in room-temperature magnetic sensor technology.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
