Inert gas condensation of evaporated Ni and laser ablated CoO


Ceylan A. , Rumaiz A. K. , Shah S. I.

JOURNAL OF APPLIED PHYSICS, vol.101, no.9, 2007 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 101 Issue: 9
  • Publication Date: 2007
  • Doi Number: 10.1063/1.2724733
  • Title of Journal : JOURNAL OF APPLIED PHYSICS

Abstract

Magnetic core/shell nanoparticles have been prepared using a method that is modified version of inert gas condensation (IGC) technique. Using resistive evaporation and laser ablation techniques combined in an IGC system, we have shown that it is possible to synthesize core/shell nanostructures made of different materials. Resistively evaporated Ni and laser ablated CoO have formed the core/shell particles. It has been found that these particles have improved magnetic properties due to their layered structures that form as a result of oxidation of Ni core before it gets coated by CoO. Investigation of magnetic properties of the particles has revealed that the particles are single domain and have superparamagnetic behavior at room temperature as a result of their small sizes. However, low temperature measurements showed that due to the exchange interactions of the different magnetically ordered layers, there is a shift of hysteresis loops for field cooled magnetization measurements. The exchange bias at 5 K obtained by 2 T field cooling of the sample was 778 Oe. (c) 2007 American Institute of Physics.