A survey of nanomagnetism

Abstract

This review is mainly concerned with size effects on the magnetic properties of low-dimensional magnetic systems. Firstly the basic physics behind the magnetism-related parameters and newly appeared phenomena such as spin polarized tunneling, oscillatory exchange coupling between magnetic-nonmagnetic multilayers, magnetoresistivyty etc., which take place in low dimensional materials are briefly addressed. Then the dependence of these parameters on the sizes of the magnetic systems are discussed as the sample dimensions are lowered from the three dinesional bulk materials through two (films, quantum wells), one (wires) and zero (quantum dots) dimensions. The critical sizes for these phenomena to be observable are also considered. Then the experimental techniques for both preparation and physical characterisation of nano-sized especially magnetic materials are summarized. The recent progresses in methods and devices and their advantage and/or disadvantages are briefly discussed as well. Lastly present situation of the technical applications of the low dimensional magnetic systems and the trends for future developments are mentioned.