Patent ID: 7746687

Claim:
A method of writing to a multi-bit MRAM memory unit comprising: setting an MRAM memory cell to a zero state level, the MRAM memory cell comprising a recording magnetic layer having a zero state level recording magnetization orientation and a free magnetic layer having a zero state level free magnetization orientation, the recording magnetization orientation in parallel relation to the free magnetization orientation; passing a read current through the MRAM memory cell to read a voltage across the MRAM memory cell; rotating the free magnetization orientation from the zero state level free magnetization orientation by reading the voltage across the MRAM memory cell until a first desired state voltage is reached to form a first desired state free magnetization orientation forming an first desired state angle with the zero state level recording magnetization orientation; heating the MRAM memory cell recording magnetic layer to a temperature above a blocking temperature of the recording magnetic layer to alter the recording magnetization orientation to be in parallel relation to the first desired state free magnetization orientation forming a first desired state recording magnetization orientation; and cooling the MRAM memory cell to a temperature below the blocking temperature of the recording magnetic layer to set the recording magnetization orientation at the first desired state recording magnetization orientation.