Biopolymer-protected GdBa2Cu3O7−x nanoparticles: Morphology, structure and superconducting properties

•GdBa2Cu3O7−x (Gd123) nanoparticles was synthesized by sol gel processing.•Biopolymer ethyl cellulose was used as an effective template in the growth of Gd123 nanoparticles.•The effect of concentration of the biopolymer on morphology and particle size were investigated.•Behavior of the magnetic susceptibility of the nanoparticles was studied in different strengths.

A synthetic procedure for the encapsulation of GdBa2Cu3O7−x superconducting nanoparticles in ethyl cellulose matrix is introduced. High resolution TEM analyses revealed that by controlling the concentration of the biopolymer and heating rate, a well-aligned nanoparticle superlattice with a diameter of about 35 nm can be readily formed. Surprisingly, the onset of superconductivity in the nanoparticles occurred at a transition temperature of 91.5 K, indicating no significant suppression of superconducting performance with the nanorod morphology. XRD data refined by Rietveld method confirmed that the crystalline structures of the nanoparticles remain in orthorhombic structure with Pmmm space group. It was found that the presence of the appropriate amount of the polymer plays a basic role as an excellent template for the nucleation and growth of the nanoparticles along the preferred direction.