Lumino-magnetic YAG:Ce nanophosphors: novel synthesis routes for efficient luminescence and magnetic properties

Abstract

Recent efforts in developing spintronic and magneto-optoelectric materials for applications have relied on the use of magnetic semiconductors doped with transition metals, but they have met with limited success. Remarkable ferromagnetism from luminescent insulators with Curie temperature above room temperature (>600 K) is an exceptional class of materials for magneto-optoelectronic and biological applications. A facile and elegant synthesis methodology is one of the key factors to achieve efficient luminescent and magnetic properties in nanoscale materials. Different strategies adopted to prepare Ce doped YAG nanophosphors have been described and their structural, luminescent and magnetic properties have been studied. It is anticipated that lattice defects (vacancies) present in the complex yttrium aluminium oxide lattice are responsible for the observed ferromagnetism and an explicit correlation emerges between defects/vacancies present in the YAG lattice with the luminescent and magnetic properties. At low synthesis temperature conditions, luminescence decreased and magnetization increased due to high defects/vacancies, and vice versa at high synthesis temperature conditions. Interestingly, the coercive field is observed to increase with increase in temperature and the possible mechanisms for these observations is discussed.