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1 INTRODUCTIONThe increasing demand for the areal density inmagnetic recording has driven the recording bit tosmaller dimensions, and it is necessary to decreasegrain size to 8 nm to achieve the areal density of155 Gb/cm2. However, with such small grainsize, the grain magnetization becomes thermallyunstable because of superparamagnetic limitation.In order to overcome the thermal instability, highanisotropy is most necessary because high magne tocrystalline anisotropy … 相似文献
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测量了巡游铁磁体SrRuO3的零场冷却(ZFC)和加场冷却(FC)的磁化强度随温度的变化关系。以及不同温度下的磁滞回线,考虑了热涨落和自由能壁垒随温度的变化,改进了Preisach模型并对测量数据进行了拟合。数据模拟再现了测量结果的变化规律,包括在不同温度下的磁滞回线和在不同外磁场下的ZFC和FC磁化强度曲线等,对拟合出的巴克豪森跳跃谱进行了讨论。 相似文献
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1 INTRODUCTIONMany works have been done in recent years onCo based granular alloys for potential applicationsas recording magnetic media[1 5]. The ideal granu lar media should consist of small and uniformgrains. High anisotropy magnetic grains embeddedin a robust non magnetic matrix are required. Highcoercivity, large squareness and negative nuclea tion field are very important for magnetic recordingfilms.The addition of Pt to the recording layer canincrease the anisotrop… 相似文献
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利用溶胶法首次制备了粒状铁钴合金纳米颗粒体,并由X射线衍射(XRD)和透射电子显微镜(TEM)进行了物相分析和颗粒形貌的观察。利用振动样品磁强计(VSM)测量了铁钴纳米颗粒体在不同温度下的磁参数。结果显示,可以通过改变制备条件得到不同颗粒尺寸,不同铁钴比例,不同SiO2含量和矫顽力不同的粒状Fe-Co-SiO2纳米颗粒体,在113~773K的温度范围内,颗粒体的饱和磁化强度和矫顽力随温度的变化非常平缓,因此,粒状FeCo-SiO2纳米颗粒体有望成为在较大温度范围内使用的磁记录介质 相似文献
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实验研究了非压缩状态下第二类哑铃畴畴壁中垂直布洛一的温度稳定性,发现与材料参量有关的两个重要温度(T^(1)0)ⅡD与(T0)ⅡD。当温度达到(T^(1)0)ⅡD时,ⅡD畴壁中的VBL开始丢失;当温度达到(T0)ⅡD时,所有ⅡD畴壁中的VBL链全部解体。 相似文献
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The magnetic properties of Nd_(16)Fe_(77)B_7 and Nd_(16)Fe_((61-x))Co_(16)Ga_xB_7(x=0,1,2,4,7)have been measured.Itis found that the remanent magnetization(Br),maximum energy product(BH)_(max)and the Curie temperature(T_c)decrease with the increase of Ga content.The coercive force(He)increases with the increase of Ga contentwhen x is less than 2,but decreases when x>2.At x=2,the coercive force reaches its maximum value.It is alsofound in all the samples investigated that there is a linear relationship between H_c~(1/2)and T~(2/3),which can not beexplained by Gaunt's wall barrier model.The temperature dependence of the calculated values of H_v and(4bf)has been discussed. 相似文献
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采用溶胶一凝胶(sol-gel)法制备了名义组分为La0.67Sr0.33-XCuXMnO3(x=0~0.33)的多晶样品,发现用Cu替代少部分Sr后样品的室温磁电阻比替代前的明显增大.在1.8T磁场作用下,当x=0.15时,磁电阻峰值为27.7%,峰值温度为306K,当温度低于306K时磁电阻值随温度的升高而增大,当温度高于306K时磁电阻值随温度的升高而减小;当x=0.1时,在295K-310K温度之间磁电阻值达19%左右,受温度影响很小;因此在提高了室温磁电阻值的同时,又提高了磁电阻的温度稳定性.这对于该类磁电阻材料的应用具有很大意义. 相似文献