Abstract
We succeeded the cluster of particles aggregation like a chain or needle by extracting from the colloidal suspension. The colloidal suspension is magnetic compound fluid (MCF) which has been developed as one of intelligent or smart fluid by one author. Also, we discovered that the size of the cluster has a memory of the applying magnetic field strength and that it has a function of the magnetic field strength. Therefore, we can control the size of the extracted or produced cluster with wide range from μm to mm. It has superparamagnetism and then we can call it a magnetic cluster.
