Sarangi S, Tan I C, Brazdeikis A
Texas Center for Superconductivity, University of Houston, Houston, TX 77204, USA.
J Nanosci Nanotechnol. 2011 May;11(5):4136-41. doi: 10.1166/jnn.2011.4112.
We have investigated and modeled the effect of interaction among magnetic particles and the magnitude and duration of external applied magnetic field on Brownian relaxation in a colloidal suspension. In the case of interacting magnetic particles, Brownian relaxation depends on the interparticle dipole-dipole interaction, which slows down the overall Brownian relaxation process of magnetic particles in the colloidal suspension. The individual magnetic particle experiences torque when a pulsatile magnetic field is applied. The torque due to the external field randomizes the particle rotation similar to that of the thermal energy. A faster Brownian relaxation is observed when individual magnetic particles are magnetized for a short duration. Magnetizing the magnetic particle for a longer duration suppress the rotational motion hence the effect of torque on Brownian relaxation.
我们研究并建立了磁性颗粒之间的相互作用以及外加磁场的大小和持续时间对胶体悬浮液中布朗弛豫影响的模型。在相互作用的磁性颗粒的情况下，布朗弛豫取决于颗粒间的偶极 - 偶极相互作用，这会减慢胶体悬浮液中磁性颗粒的整体布朗弛豫过程。当施加脉动磁场时，单个磁性颗粒会受到转矩作用。外部磁场产生的转矩使颗粒旋转随机化，类似于热能的作用。当单个磁性颗粒被短时间磁化时，会观察到更快的布朗弛豫。将磁性颗粒长时间磁化会抑制旋转运动，从而抑制转矩对布朗弛豫的影响。
