Enhancement in Curie Temperature of Yttrium Iron Garnet by Doping with Neodymium.

Esperanza Baños-López,Ana Bolarín-Miró,Claudia Cortés-Escobedo,Félix Sánchez-De Jesús,Arturo Barba-Pingarrón

doi:10.3390/ma11091652

Abstract

The effect of the substitution of Y3+ by Nd3+ on the structural and magnetic properties of neodymium-doped yttrium iron garnet, NdxY3−xFe5O12 with x in the range of 0–2.5, is presented. Oxide powders of Fe2O3, Nd2O3, and Y2O3 were mixed in a stoichiometric ratio and milled for 5 h using high-energy ball milling, before being uniaxially pressed at 900 MPa and annealed at 1373 K for 2 h to obtain NdxY3−xFe5O12 (0 ≤ x ≤ 2.5). It was found that the mechanical milling of oxides followed by annealing promotes the complete structural formation of the garnet structure. Additionally, the X-ray diffraction patterns confirm the complete introduction of Nd3+ into the garnet structure with a neodymium doping concentration (x) of 0–2.0, which causes a consistent increment in the lattice parameters with the Nd3+ content. When x is higher than 2.0, the yttrium orthoferrite is the predominant phase. Besides, the magnetic results reveal an increase in the Curie temperature (583 K) as the amount of Nd3+ increases, while there was enhanced saturation magnetization as well as modified remanence and coercivity with respect to non-doped YIG.

Highlights

Yttrium iron garnet, Y3 Fe5 O12 (YIG) that contain only trivalent ions, has been receiving attention for a long time due to its remarkable properties, such as high electrical resistivity (ρ = 108 Ωm), low dielectric losses, high relative permittivity, medium saturation magnetization (Ms = 26 emu/g), and low coercivity (Hc = 17 Oe) [1,2,3,4].The ferrimagnetic garnet, which has secondary symmetry, crystallizes in a cubic structure (space group Ia3d (Oh 10 ) with eight formula units and three sub-lattices
Ndx Y3−x Fe5 O12 according with the inorganic crystal structure database (ICSD) #1008628 (Ia3d), which did not have peaks corresponding to the precursors
The formation of the orthoferrite phases instead of a garnet phase is due to the limit of the solubility of neodymium into the yttrium iron garnet (YIG) structure

Summary

Introduction

The ferrimagnetic garnet, which has secondary symmetry, crystallizes in a cubic structure (space group Ia3d (Oh 10 ) with eight formula units and three sub-lattices. Of these sub-lattices, one is occupied by Y3+ diamagnetic ions (or rare earth ions) in dodecahedral sites {24c} according to the Wyckoff notation. The second is occupied by Fe3+ magnetic ions that distribute in octahedral 16a sites, which are distorted along one of the three fold axes. This trigonal axis coincides with the [111] direction. Due to the incorporation of doping cations into the structure of YIG, this causes changes in the magnetic, structural, and magneto-optical properties [11]

Methods

Results

Conclusion