Arekapudi Sri Sai Phani Kanth, Bülz Daniel, Ganss Fabian, Samad Fabian, Luo Chen, Zahn Dietrich R T, Lenz Kilian, Salvan Georgeta, Albrecht Manfred, Hellwig Olav
Institute of Physics, Chemnitz University of Technology, 09107 Chemnitz, Germany.
Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, 01328 Dresden, Germany.
ACS Appl Mater Interfaces. 2021 Dec 15;13(49):59497-59510. doi: 10.1021/acsami.1c18017. Epub 2021 Dec 6.
Antiferromagnets (AFMs) with zero net magnetization are proposed as active elements in future spintronic devices. Depending on the critical film thickness and measurement temperature, bimetallic Mn-based alloys and transition-metal oxide-based AFMs can host various coexisting ordered, disordered, and frustrated AFM phases. Such coexisting phases in the exchange coupled ferromagnetic (FM)/AFM-based heterostructures can result in unusual magnetic and magnetotransport phenomena. Here, we integrate chemically disordered AFM γ-IrMn thin films with coexisting AFM phases into complex exchange coupled MgO(001)/γ-NiFe/γ-IrMn/γ-NiFe/CoO heterostructures and study the structural, magnetic, and magnetotransport properties in various magnetic field cooling states. In particular, we unveil the impact of rotating the relative orientation of the thermally disordered and reversible AFM moments with respect to the irreversible AFM moments on the magnetic and magnetotransport properties of the exchange coupled heterostructures. We further reveal that the persistence of thermally disordered and reversible AFM moments is crucial for achieving highly tunable magnetic properties and multilevel magnetoresistance states. We anticipate that the presented approach and the heterostructure architecture can be utilized in future spintronic devices to manipulate the thermally disordered and reversible AFM moments at the nanoscale.
净磁化强度为零的反铁磁体（AFM）被提议作为未来自旋电子器件中的有源元件。根据临界薄膜厚度和测量温度，双金属锰基合金和过渡金属氧化物基反铁磁体可以容纳各种共存的有序、无序和受挫反铁磁相。基于交换耦合铁磁（FM）/反铁磁体的异质结构中的这种共存相可导致异常的磁和磁输运现象。在此，我们将具有共存反铁磁相的化学无序反铁磁体γ-IrMn薄膜集成到复杂的交换耦合MgO(001)/γ-NiFe/γ-IrMn/γ-NiFe/CoO异质结构中，并研究各种磁场冷却状态下的结构、磁性和磁输运性质。特别是，我们揭示了将热无序且可逆的反铁磁矩相对于不可逆反铁磁矩的相对取向旋转对交换耦合异质结构的磁性和磁输运性质的影响。我们进一步表明，热无序且可逆的反铁磁矩的持续存在对于实现高度可调的磁性和多级磁阻状态至关重要。我们预计，所提出的方法和异质结构架构可用于未来的自旋电子器件中，以在纳米尺度上操纵热无序且可逆的反铁磁矩。
