Thermal stability of exchange bias systems based on MnN

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Abstract

At the present time there is a requirement to identify new antiferromagnetic alloys or compounds which might be suitable for the production of exchange bias systems. The phenomenon of exchange bias remains crucial for the operation of all read heads in hard disk drives and also has potential for use in magnetic random access memory (MRAM) systems. There is also an increasing interest in the use of antiferromagnets themselves in spintronic devices. Generally for applications the alloy IrMn is used, however given that Iridium is one of the rarest, and therefore most expensive elements on Earth, there is a search for alternative materials. In this paper we report on a study of the compound MnN in terms of its thermal stability. We have produced polycrystalline films of this compound with sub 10 nm grains and examined the thermal stability in layers of thicknesses of up to 30 nm. Using thermal activation studies we have determined a room temperature value of the anisotropy constant of this compound in a tetragonal structure of up to (6.3 ± 0.3) × 10 6 erg/cm 3 . The antiferromagnetic grains can be aligned by thermal annealing at an optimum temperature of 380 K. Above this temperature the magnetic properties deteriorate possibly due to nitrogen desorption.

Original languageEnglish
Pages (from-to)278-283
Number of pages6
JournalJournal of Magnetism and Magnetic Materials
Volume476
Early online date14 Dec 2018
DOIs
Publication statusPublished - 15 Apr 2019

Bibliographical note

Funding Information:
The authors would like to thank Dr. Stephen McVitie from the University of Glasgow for valuable help with TEM sample preparation. This work was part-funded through a project, HARFIR (Heusler Alloy Replacement For Iridium), by the European Commission under the 7th Framework Programme (FP7-NMP-2013-EU-Japan, Grant Agreement No. NMP3-SL-2013-604398). AH, GVF and KOG also acknowledge financial support from the UK EPSRC (EP/M02458X/1).

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