According to a report from Japan, TDK Corp is going to present a prototype 8-Mbit STT-MRAM device today at Ceatec Japan 2014. The MRAM was produced on a 8" silicon substrate. Hopefully TDK will give more details on this achievement later today.
The report further says that TDK aims to commercialize STT-MRAM chips in 3-5 years.
Source: Nikkei technology