Remarkable magnetic anisotropy of nickel nanocrystals growth with dominantly exposed {1 1 1} facets in coir fiber pores

Abstract

The synthesis of nickel nanocrystals in coir fiber pores by a two-step method (co-precipitation and lyophilization) has been demonstrated. XRD analysis proved the face-centered cubic crystal structure of nickel with the space group Fm3¯m. Nickel nanocrystals of 8.5 nm in size with dominantly exposed {111} planes, embedded in a coir fiber matrix, were determined. Scanning electron microscopy clearly showed that the nickel nanocrystals in the coir fiber pores were assembled in large aggregate nanoplates-like structures arrayed along the drawing direction. Room temperature magnetic measurements showed that nickel nanocrystal in the coir fiber exhibit typical ferromagnetic behavior at room temperature. A different response of the magnetization (M⊥ > M||) was also observed when measured with H|| or H⊥ in the drawing direction. This behavior was attributed to a magnetic anisotropy effect due to the preferred orientation of the crystal aggregates.