溅射NdFeB薄膜合金的磁各向异性

用RF溅射方法在不同的基片温度下制备了非晶态和晶态NdFeB溥膜合金。研究了薄膜合金的磁各向异性。在600℃溅射得到的晶态样品具有强的垂直各向异性和高的矫顽力。由非晶态晶化得到的晶态合金也呈现了较强的垂直各向异性。

MAGNETIC MOMENT AND CURIE TEMPERATURE OF AMORPHOUS (Fe_(100-x)B_(x))_(88)Nd_(12±ε) ALLOYS

The magnetization curves at 1.5K and Curie temperature of amorphow (Fe_(100-x)B_(x))_(88)Nd_(12±ε) alloys were measured.Their spontaneous magnetizations is explained by a noncollinear structure.The average magnetic moment μ_(Fe) per Fe atom decreases monotonically with increasing x,and becomes more rapid when x>24.The B content dependence of Curie temperature shows a mazimum at x=15.At x<15,the increase of T_(c) with x may be attributed to the indirect exchange interactions between Fe-Fe atoms.

MAGNETIC PROPERTIES OF HEAT TREATED Nd_(3)Fe_(81)B_(16) ALLOY

The hysteresis loop and Mdssbauer spectrum of the heat treated Nd_(3)Fe_(81)B_(16) alloy ribbons annealing at 660℃ for lOmin.have been measured.A coercive field of about 2kOe and an energy product of about 8MGOe are obtained at room temperature.X-ray diffraction and Mdssbauer spectrum analyses show that the high coercivity may originate from the Fe_(3)B phase containing Nd.The value of remanence and energy product in this alloy are much higher than those of anisotropic BaFe_(12)O_(19) ferrite.It may be used as a cheap permanent magnet.

非晶Nd_3Fe_(81)B_(16)合金的晶化及其对磁性和Mssbauer谱的影响

本文报道利用单辊方法制备的非晶Nd_3Fe_(81)B_(16)合金的晶化及其对磁性和Mossbauer谱的影响。发现在非晶Fe_(81)B_(19)合金中用3at％Nd取代B,使非晶Fe_(81)B_(19)合金的晶化温度提高88℃。在适当的退火条件下晶化后样品在室温下的磁性是:σ_2=189emu/g,σ_r/σ_5=0.7,_iH_c=2.15kOe,B_r≈12kG,_bH_c=2kOe,(BH)_(max)≈8MGOe。与目前广泛使用的六角铁氧体相比,_bH_c相近,但B_r和(BH)_(max)远比六角铁氧体高。这种材料仅含有少量的Nd,因此可能开发为一种新的廉价永磁材料。本文对少量Nd的添加对非晶FeB合金的晶化温度,磁性和Mossbauer谱的影响进行了讨论。初步探讨了高矫顽力的来源,认为它的磁化和反磁化过程可以用畴壁钉扎理论解释。