Apparent magnetic energy-barrier distribution in horse-spleen ferritin : Evidence for multiple interacting magnetic entities per ferrihydrite nanoparticle
Apparent magnetic energy-barrier distribution in horse-spleen ferritin : Evidence for multiple interacting magnetic entities per ferrihydrite nanoparticle
复制标题
马脾铁蛋白中的表观磁能垒分布：每个水铁矿纳米颗粒存在多个相互作用的磁性实体的证据
DOI：
10.1103/physrevb.65.024436
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发表时间：
2001
影响因子：
3.7
通讯作者：
K. V. Rao
中科院分区：
文献类型：
--
作者：
T. Pierre;N. Gorham;P. Allen;J. Costa;K. V. Rao
对天然马脾铁蛋白在2 ~ 21 K的零外加磁场条件下的磁性粘度进行了测定。利用所得数据计算了铁蛋白样品的视磁矩加权能垒分布。该分布由对数正态分布和第二个分布组成，第二个分布很好地描述了势垒频率随势垒高度的指数衰减。这两种分布对总体分布的贡献大致相等。对数正态分布的峰值约为3 × 10 - 21 j，而第二种分布的衰减常数约为2 × 10 - 21 j。具有指数衰减形状的低能势垒分布的存在，结合移场冷却磁滞回线的观测，被解释为每个铁蛋白粒子中存在多个相互作用的磁实体的有力证据。
Magnetic viscosity measurements were made on native horse-spleen ferritin in zero applied magnetic field at temperatures between 2 and 21 K. The data have been used to calculate the apparent magnetic-moment-weighted energy barrier distribution for the sample of ferritin. The distribution is composed of a log-normal distribution plus a second distribution that is well described by an exponential decay of barrier frequency with increasing barrier height. The two distributions contribute approximately equally to the overall distribution. The log-normal distribution has its peak at an energy barrier of approximately 3 × 10 - 2 1 J. while the decay constant for the second distribution has a value of approximately 2 X 10 - 2 1 J. The existence of the low-energy barrier distribution with exponentially decaying shape in conjunction with the observation of shifted field-cooled magnetic hysteresis loops is interpreted as strong evidence for the existence of multiple interacting magnetic entities within each ferritin particle.