- A material for data storage is developed aiming at the substitution of traditionally used ferromagnetics
- Tapes made of the antiferromagnetic material provide a new, versatile and safer support for the storage of information
- The research is fruit of a collaboration of ICMAB-CSIC with the ALBA Synchrotron
A primer about data storage materials
Ferromagnetics are a widely used type of magnetic materials in data-storage applications such as credit cards, intelligent ID cards or conventional computer hard drives, among other uses. To date, ferromagnetics are the most widely used support worldwide to encode information. Alas, one of their main disadvantages is that the stored data may become corrupted or erased under certain conditions.
Antiferromagnetics offer a more robust alternative for storing information than ferromagnetic materials. A group of researchers of the Institute of Materials Science of Barcelona (ICMAB-CSIC), in collaboration with the ALBA Synchrotron, have obtained a flexible tape made of an antiferromagnetic material (an iron-rhodium system, FeRh). This tape could substitute ubiquitously used ferromagnetic materials such as barium ferrite for data storage.
An advantageous alternative to ferromagnetics
The novel material is capable of storing information in a more robust and secure way than commonly used ferromagnetics and can be of application where both physical flexibility and robustness and realiability of data storage are required.
The innovation, published in Applied Materials and Interfaces, can be integrated into flexible or wearable devices. The developmet, made of an iron-rhodium (FeRh) alloy, on the one hand displays the necessary antiferromagnetic characteristics while also being flexible and having the required crystalline structure. As an additional advantage, the material is especially easy to manipulate owing to the fact that it presents a transition from antiferromagnetic to ferromagnetic behaviour at conditions close those of room temperature.
"Ferromagnets have been known for thousands of years and their behavior has been extensively studied. Antiferromagnetics, in which the magnetic moments of the atoms are spontaneously aligned antiparallel to the neighboring moments, can be used to store information, following certain protocols, providing greater security than ferromagnets", explains Ignasi Fina, ICMAB researcher and first author of the article.
Until now, FeRh alloy materials had not been integrated in conventional flexible devices, grown on polymeric substrates, because they need to show a good crystalline structure. This entails that the atoms need to be arranged in a certain order that allows stabilizing the antiferromagnetic ordering. In practice, this typically resulted in FeRh alloys being usually prepared on monocrystalline substrates, which in turn made them rigid and potentially fragile, hence unsuitable for certain applications requiring flexibility.
A challenge overcome:
"It is especially difficult to obtain a flexible material with a crystalline structure. Since the properties of materials utterly depend on their structure, it is very important to obtain the material with a good crystallinity, which is what gives FeRh its unique properties for data recording", adds researcher Ignasi Fina.
The study by Fina and colleagues gives proof of the robustness of the properties of the material under bending forces, and of the information stored on the tapes, which could be fabricated in meters-long stretches of material, proving the affordability and feasibility of its scale-up.
"These flexible antiferromagnetic tapes have multiple applications in secure and robust magnetic recording, and could be integrated in real flexible or wearable devices, such as credit cards or identification cards, where security and robustness against electromagnetic radiation, for example from cell phones, is extremely important. Other possible niche applications are likely to emerge when suitable prototypes become available" concludes the ICMAB researcher.
Pictures of the flexible tape and tape cross-section were used with permission of ICMAB.