Investigation of phase transformation behavior in sputter deposited PtMn thin films
Sputter-deposited, equiatomic PtMn thin films have application in giant magnetoresistive spin valves, tunneling magnetoresistive spin valves, and magnetic random access memory. However, the as-deposited films are found to be a disordered A1 phase in a paramagnetic state rather than an antiferromagnetic phase with L1{sub 0} structure, which is needed for device operation. Therefore, a postannealing step is required to induce the phase transformation from the as-deposited A1 face-centered-cubic phase to the antiferromagnetic L1{sub 0} phase. The A1 to L1{sub 0} metastable transformation was studied by x-ray diffraction and differential-scanning calorimetry. An exothermic transformation enthalpy of -12.1 kJ/mol of atoms wasmore »