Example embodiments of the present invention disclose a semiconductor memory device and a method of forming a memory device. A semiconductor memory device may include a digit line disposed on a substrate, an intermediate insulating layer covering the digit line, a magnetic tunnel junction (MTJ) pattern disposed on the intermediate insulating layer and over the digit line, the MTJ pattern including a sequentially stacked lower magnetic pattern, upper magnetic pattern, and capping pattern, wherein the capping pattern does not react with the upper magnetic pattern at a temperature above about 280° C., and a bit line connected to the capping pattern and disposed to intersect the digit line. A method of forming a semiconductor memory device may include forming a digit line on a substrate, forming an intermediate insulating layer covering the digit line, forming a magnetic tunnel junction (MTJ) pattern on the intermediate insulating layer, the MTJ pattern including a sequentially stacked lower magnetic pattern, upper magnetic pattern, and capping pattern, wherein the capping pattern does not react with the upper magnetic pattern at a temperature above about 280° C., performing an annealing operation at a temperature of about 350° C. or higher, and forming a bit line connected to the capping pattern and disposed to intersect the digit line.