Structural defects and magnetic properties of gadolinium silicide nanoparticles synthesized by laser ablation technique in liquid

Abstract

Magnetic nanoscale compounds and alloys of gadolinium are promising materials for technological and medical applications. In this paper the influence of structural defects on the properties of the binary GdSi nanopowders formed in laser ablation and post‐irradiation processes have been investigated. To obtain compound GdSi nanoparticles (NPs) we used laser ablation of a combined target consisting of Gd and Si plates tightly pressed to each other with focusing a laser beam onto the gadolinium–silicon interface. The crystalline structure, phase composition of the NPs formed were examined by SEM and X‐ray diffraction (XRD). Magnetic measurements showed that the resulting NPs did not exhibit hysteresis at low temperature (6 K), which is typical to nanosized magnetic materials demonstrating superparamagnetic behavior. Magnetization increased after laser processing of the samples due to ordering in the grain structure and in the magnetic moments at the surface. magnified image

Manifestation of coherent magnetic anisotropy in a carbon nanotube matrix with low ferromagnetic nanoparticle content

“…In the intermediate temperature interval (T = 100-200 K) the experimental data can also be fitted with the Laplace integrals ≈ − F p p ( ) 1 and ≈ − F p p ( ) 2 . The first Laplace integral leads to the correlation function 3 2 while the second one gives 4 Note that equations (11) and (12) are valid for r >1, while for ⩽ ⩽ r 0…”

“…Actually, matrix materials like polymers [6], silica [7], porous silicon [8], and carbon nanotubes (CNT) [9] are widely used nowadays. NPs are introduced into the matrix material in various ways, like co-precipitation, thermal decomposition, hydrothermal synthesis [10], co-evaporation and co-sputtering [6], laser ablation [11], electrochemical processes [12], ion implantation [13], and chemical vapor deposition [9]. Actually, the greatest demand is for nanocomposites in which single domain NPs interact weakly with each other.…”

ZnO nanorods prepared via ablation of Zn with millisecond laser in liquid media

“…Amongst metal oxides, ZnO is probably one of the most investigated semiconductor materials and accordingly its nanostructures have been synthesized by various methods, such as (to name a few) solvothermal synthesis [22][23][24]27,[30][31][32], microwave irradiation [31,33], and CVD [26,27]. The LAL method was also applied, and both doped and non-doped, as well as surface-stabilized or non-stabilized, ZnO nanoparticles (NPs) with different morphologies and sizes were reported [4][5][6][7][8][9][10]12,[14][15][16][17][18][34][35][36].…”

“…In the last decade, laser ablation in liquid (LAL) has proven to be an attractive, simple, and efficient technique to generate a large variety of nanostructures of diverse materials. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] In this approach, laser beam is typically focused on a solid (often metal) target immersed into a liquid and produces various nanostructures whose chemistry, morphology and size distribution are defined by both the laser pulse parameters and the liquid. 1,2,17 This technique is attractive as a green approach using minimum solvents, easy-to-use, and even sometimes capable of controlling the morphology of produced nanomaterials.…”

Pulsed Laser in Liquids Made Nanomaterials for Catalysis

“…Svrcek et al laser-synthesized room-temperature luminescent silicon nanocrystals with low surface defect densities . Tarasenka et al investigated structural defects and magnetic properties of laser-made gadolinium silicide nanoparticles . Singh and co-workers laser-synthesized TiO 2 and ZnO nanoparticles that exhibited intrinsic room temperature ferromagnetism; they attributed the observed ferromagnetism to predominant defect centers, which were single ionized oxygen and neutral zinc vacancies in ZnO and oxygen and neutral or ionized titanium vacancies in TiO 2 .…”