All-Electric Access to the Magnetic-Field-Invariant Magnetization of Antiferromagnets

Abstract

The rich physics of thin film antiferromagnets can be harnessed for prospective spintronic devices given that all-electric assessment of the tiny uncompensated magnetic moment is achieved. On the example of magnetoelectric antiferromagnetic Cr2O3, we prove that spinning-current anomalous Hall magnetometry serves as an all-electric method to probe the field-invariant uncompensated magnetization of antiferromagnets. We obtain direct access to the surface magnetization of magnetoelectric antiferromagnets providing a read-out method for ferromagnet-free magnetoelectric memory. Owing to the great sensitivity, the technique bears a strong potential to address the physics of antiferromagnets. Exemplarily, we apply the method to access the criticality of the magnetic transition for an antiferromagnetic thin film. We reveal the presence of field-invariant uncompensated magnetization even in 6-nm-thin IrMn films and clearly distinguish two contributions, of which only the minor one is involved in interfacial magnetic coupling. This approach is likely to advance the fundamental understanding of the anomalous Hall and magnetic proximity effects.

Spin-Hall-Effect-Assisted Electroresistance in Antiferromagnets via 105 A/cm2 dc Current

“…The exchange bias in Figure S1 suggests parallel orientation between the cooling field and the AFM moments in FeMn. Recently with growing attention to AFM spintronics, it has been demonstrated that the cooling field lower than the threshold value also creates collinear alignments of AFM moments in plain AFM layers ( e.g ., Cr 2 O 3 , IrMn)2425. The threshold field is quite large for most AFMs, for example, 6 T for Cr 2 O 3 26.…”

“…The field-cooling process excludes isotropic effects such as substrate morphology, tunneling at grain boundaries, and domain wall motions, and reflects the anisotropic AFM order parameters. In addition, the resistance reduction cannot be ascribed to neither current-induced Joule heating nor the magnetic proximity effect (MPE) in Pt induced by the interfacial uncompensated moments in FeMn24, because the rising temperature only leads to increasing resistance (Fig. 1a), while the MPE generally causes at most several-Ohm shift of the total resistance (Supplementary Figure S4).…”

Spin Hall effects in metallic antiferromagnets – perspectives for future spin-orbitronics

“…[29][30][31][32][33][34][35][36] Given the growing interest in metallic AFs, 37 another natural question is whether they are capable of generating efficient spin currents through the direct spin Hall effects, as predicted by Onsager reciprocal relations. We recently confirmed large spin current generation from such metallic AFs, in particular PtMn, through ST-FMR experiments.…”

Magnetoelectric domain wall dynamics and its implications for magnetoelectric memory

“…Alternatively, the AFM domain state can be detected through the anomalous Hall effect in a thin non-magnetic control gate. 28 Since the domain wall should fit inside the bit, its width d sets a limitation for the downward scaling of the length of the MEAF element. The width of this element, however, can be significantly smaller.…”