HARFIR- Heusler Alloy Replacement for Iridium

  • FB Physik
    Hirohata, Atsufumi; Huminiuc, Teodor; Sinclair, John; Wu, Haokaifeng; Samiepour, Marjan; Vallejo-Fernandez, Gonzalo; O’Grady, Kevin; Balluf, Jan; Yanes Díaz, Rocio; Nowak, Ulrich(2017): Development of antiferromagnetic Heusler alloys for the replacement of iridium as a critically raw material Journal of Physics D : Applied Physics ; 50 (2017), 44. - 443001. - ISSN 0022-3727. - eISSN 1361-6463

Development of antiferromagnetic Heusler alloys for the replacement of iridium as a critically raw material

As a platinum group metal, iridium (Ir) is the scarcest element on the earth but it has been widely used as an antiferromagnetic layer in magnetic recording, crucibles and spark plugs due to its high melting point. In magnetic recording, antiferromagnetic layers have been used to pin its neighbouring ferromagnetic layer in a spin-valve read head in a hard disk drive for example. Recently, antiferromagnetic layers have also been found to induce a spin-polarised electrical current. In these devices, the most commonly used antiferromagnet is an Ir–Mn alloy because of its corrosion resistance and the reliable magnetic pinning of adjacent ferromagnetic layers. It is therefore crucial to explore new antiferromagnetic materials without critical raw materials. In this review, recent research on new antiferromagnetic Heusler alloys and their exchange interactions along the plane normal is discussed. These new antiferromagnets are characterised by very sensitive magnetic and electrical measurement techniques recently developed to determine their characteristic temperatures together with atomic structural analysis. Mn-based alloys and compounds are found to be most promising based on their robustness against atomic disordering and large pinning strength up to 1.4 kOe, which is comparable with that for Ir–Mn. The search for new antiferromagnetic films and their characterisation are useful for further miniaturisation and development of spintronic devices in a sustainable manner.

Origin (projects)

    Yanes, Rocio; Simon, Eszter; Keller, Sebastian; Nagyfalusi, Balazs; Khmelevsky, Sergii; Szunyogh, Laszlo; Nowak, Ulrich(2017): Interfacial exchange interactions and magnetism of Ni2MnAl/Fe bilayers Physical Review B ; 96 (2017), 6. - 064435. - ISSN 2469-9950. - eISSN 2469-9969

Interfacial exchange interactions and magnetism of Ni<sub>2</sub>MnAl/Fe bilayers

Based on a multi-scale calculations, combining ab-initio methods with spin dynamics simulations, we perform a detailed study of the magnetic behavior of Ni<sub>2</sub>MnAl/Fe bilayers. Our simulations show that such a bilayer exhibits a small exchange bias effect when the Ni<sub>2</sub>MnAl Heusler alloy is in a disordered B2 phase. Additionally, we present an effective way to control the magnetic structure of the Ni<sub>2</sub>MnAl antiferromagnet, in the pseudo-ordered B2-I as well as the disordered B2 phases, via a spin-flop coupling to the Fe layer.

Origin (projects)

Funding sources
NameProject no.DescriptionPeriod
Sonstige EU400Kommission der Europäsischen Gemeinschaften17.07.2013 – 31.03.2017
Further information
Period: 01.09.2013 – 31.03.2017