Scientists at Hokkaido University have developed a device that employs both magnetic and electronic signals, which could provide twice the storage capacity of conventional memory devices, such as USB flash drives.
The team at Hokkaido University’s Research Institute for Electronic Science investigated the possibility of using a magnetic signal along with the electronic signal to allow double the storage capacity in these ‘multiplex writing/reading’ devices. In addition to the binary 0/1 method of storing information, this would add an A/B store for the information as well. To do this would require finding a material that can switch back and forth from a magnetic to a non-magnetic state.
Utilizing two types of strontium cobalt oxide with various oxygen content, the device can be switched from a insulating/non-magnetic state to a metallic/magnetic state all the while by electrochemical oxidation/decrease response at room temperature in air.
The team investigated two forms of strontium cobalt oxide (SrCoOx): one is an insulating non-magnet while the other is a metal magnet. By changing the oxygen content in this compound, the team could cause it to switch between the two forms. However, the two methods currently available to do this have big drawbacks. One method requires using a high temperature heat treatment, making it impossible to use in devices that work at room temperature. The other method involves using a dangerous alkaline solution, which would require a device that is sealed so that the solution does not leak. This method is difficult to miniaturise and is thus not suitable for information storage devices.
The group developed up another strategy to utilize strontium cobalt oxide securely at room temperature in air. They connected a sodium tantalate thin film, which can be utilized at room temperature without leaking alkaline solution, over layers of strontium cobalt oxide. At the point when a 3V current was applied, the insulating form of SrCoO2.5 reversibly switched to its metal magnet form, SrCoO3, By comparison, current devices can store information in 0.01 seconds.