The magnetic switching properties of magnetic tunnel junctions (MTJ) using a synthetic ferrimagnet (SyF) free layer were studied. The free layers were deposited on a thermally oxidized Si substrate by an ultrahigh vacuum sputtering system. The tunneling magnetoresistance (TMR) curves were measured using a dc four probe method. It was observed that the SyF free layer showed a size independent switching field for all element widths from 0.25 to 16 μm. Large TMR ratio up to 40% was exhibited by the MTJs after annealing at 250 °C.