She was a contemporary of Tchaikovsky at the Saint Petersburg Conservatory, and graduated from Teodor Leszetycki's piano class in 1865. From 1887 until 1908 she was professor of piano at the Saint Petersburg Conservatory.
Correspondence with Tchaikovsky
One letter from Tchaikovsky to Sofya Malozemova has survived, dating from 1883, and has been translated into English on this website:
4 letters from Malozemova to Tchaikovsky, dating from around 1875 to 1883, are preserved in the Klin House-Museum Archive.