一种低磁矩、大功率复合稀土石榴石铁氧体的工艺和性能研究

Preparation and Properties of A New High-Power Composite Rare-Earth Garnet Ferrite with Low Magnetic Moments

为满足低场区几百兆赫的超大功率器件的性能要求,以钇铁石榴石铁氧体为基础,制备了一种低磁矩复合稀土石榴石铁氧体YGd CaVInIG,研究了少量Mn3+替代Fe3+和预烧温度、烧结温度对铁氧体性能和结构的影响。实验表明,以少量Mn3+替代Fe3+可以提高铁氧体电阻率,降低磁损耗和介电损耗。Mn3+掺入量以x为0.04～0.06比较合适,铁氧体最佳予烧温度为1050℃,最佳烧结温度1350～1380℃,保温5h,氧气中烧结,其性能为:4πMs=500±10%kA·m-1,ΔH=5.25～5.55kA·m-1,TC>180℃,tgδe≤0.5×10-5,这种材料适合微波低频段器件性能要求。X射线衍射分析指出,掺Mn3+的YGdCaVInIG铁氧体相变完全,呈单相复合石榴石铁氧体,空间群为I230,点阵常数1.25057～1.25101nm,单胞分子数n为7.75～7.80。

Based on the yttrium garnet ferrite, a composite rareearth garnet ferrite with low magnetic moments, YGdCaVInIG, was designed and prepared to meet the need of super power device which works in low field at a few hundreds of megahertz bands. The small amount substitution of Mn3+ for Fe3+ ions, precalcined temperature and sintered temperature effects on the properties and structures of the ferrite were studied. It was found that small amount of substitution of Mn3+ for Fe3+ ions could improve the resistivity and decrease the magnetic and dielectric losses. The optimal doping level of Mn3+ for Fe3+ of the ferrite, x, is found to be in the range of 0.04～0.06, while the optimal precalcined temperature is 1050 ℃ and the sintered temperature 1350～1380 ℃ for 5 h in O2 gas. The main parameters of the ferrite are as follows, 4πMs=500±10% kA·m-1, ΔH=5.25～5.55 kA·m-1, TC>180 ℃, tgδe ≤0.5×10-5, which quite meets the need of lowfrequency microwave device. Xray diffraction analysis reveals that Mn3+ doped YGdCaVInIG ferrite has a well single phase with the space group of I230, lattice parameter ranging from 1.25057 to 1.25101 nm, and the molecular number n per unit cell is 7.75～7.80.