Fabrication of nanoconstriction to study the change in magnetoresistance of a (Ga,Mn)As strip as a function of construction size

The physical properties of materials are substantially modified when the lateral dimensions become of the same order of magnitude as certain characteristic lengths. Recent activities have evolved towards reducing not only the thickness but also the lateral dimensions of the material down to nanometer sizes. This has been made possible by using advanced pattering techniques such as electron been lithography and ultrasonically assisted development [1]. Regarding magnetoresistance, very recently, a magnetoresistance of -2000% have been reported in ferromagnetic GaMnAs nanocontacts [2]. This effect is called nanocontacts magnetoresistance.