Magnetic Properties of Nanoparticles Useful for SQUID Relaxometry in Biomedical Applications.
Magnetic Properties of Nanoparticles Useful for SQUID Relaxometry in Biomedical Applications.
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DOI：
10.1016/j.jmmm.2010.10.042
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发表时间：
2011-03-01
影响因子：
2.7
通讯作者：
Flynn ER
中科院分区：
文献类型：
--
作者：
Bryant HC;Adolphi NL;Huber DL;Fegan DL;Monson TC;Tessier TE;Flynn ER
我们使用动态磁电阻测量提取半经验温度依赖性，255至400 K，磁性参数，确定在生物医学应用中的SQUID弛豫有用的单核纳米粒子的行为。在0.1 - 1000 Hz范围内的9个频率下，以5 K度步长进行体积磁化率测量，具有0.2 mT振幅探测场。饱和磁化强度（Ms）和各向异性能量密度（K）从拟合的理论磁化率的测量都随着温度的降低而增加，分别从真实的和虚部的参数值之间的良好的协议得到。Néel弛豫时间的表征表明，传统的前因子，0.1纳秒，是一个上限，与各向异性能量密度强相关。随着K的增加，该前因子在较低温度下显著降低。我们发现，使用确定的参数值从真实的部分的磁化率测量在300 K，SQUID弛豫测量的弛豫和激发曲线上相同的样品进行了很好的描述。
We use dynamic susceptometry measurements to extract semiempirical temperature-dependent, 255 to 400 K, magnetic parameters that determine the behavior of single-core nanoparticles useful for SQUID relaxometry in biomedical applications. Volume susceptibility measurements were made in 5K degree steps at nine frequencies in the 0.1 – 1000 Hz range, with a 0.2 mT amplitude probe field. The saturation magnetization (Ms) and anisotropy energy density (K) derived from the fitting of theoretical susceptibility to the measurements both increase with decreasing temperature; good agreement between the parameter values derived separately from the real and imaginary components is obtained. Characterization of the Néel relaxation time indicates that the conventional prefactor, 0.1 ns, is an upper limit, strongly correlated with the anisotropy energy density. This prefactor decreases substantially for lower temperatures, as K increases. We find, using the values of the parameters determined from the real part of the susceptibility measurements at 300 K, that SQUID relaxometry measurements of relaxation and excitation curves on the same sample are well described.
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影响因子：
2.7
作者：
RAIKHER, YL
通讯作者：
RAIKHER, YL
影响因子：
2.7
作者：
Adolphi NL;Huber DL;Jaetao JE;Bryant HC;Lovato DM;Fegan DL;Venturini EL;Monson TC;Tessier TE;Hathaway HJ;Bergemann C;Larson RS;Flynn ER
通讯作者：
Flynn ER
影响因子：
3.2
作者：
Bentivegna, F;Ferre, J;Boilot, JP
通讯作者：
Boilot, JP
影响因子：
3.7
作者：
Raikher, YL;Stepanov, VI
通讯作者：
Stepanov, VI
影响因子：
3.7
作者：
Chantrell, RW;Walmsley, N;Maylin, M
通讯作者：
Maylin, M