Negative spin Hall magnetoresistance in antiferromagnetic Cr2O3/Ta bilayer at low temperature region

Abstract

We investigate the observation of negative spin Hall magnetoresistance (SMR) in antiferromagnetic Cr2O3/Ta bilayers at low temperature. The sign of the SMR signals is changed from positive to negative monotonously from 300 K to 50 K. The change of the signs for SMR is related with the competitions between the surface ferromagnetism and bulky antiferromagnetic of Cr2O3. The surface magnetizations of α-Cr2O3 (0001) is considered to be dominated at higher temperature, while the bulky antiferromagnetics gets to be robust with decreasing of temperature. The slopes of the abnormal Hall curves coincide with the signs of SMR, confirming variational interface magnetism of Cr2O3 at different temperature. From the observed SMR ratio under 3 T, the spin mixing conductance at Cr2O3/Ta interface is estimated to be 1.12 × 10 14 Ω -1 · m -2 , which is comparable to that of YIG/Pt structures and our early results of Cr2O3/W. (Appl. Phys.Lett. 110, 262401 (2017)) a) Electronic

Magnetic order of Dy3+ and Fe3+ moments in antiferromagnetic DyHoogeboom1, Kuschel2, Bauer3 et al. 2021Phys. Rev. B17071View full textAdd to dashboardCite

“…SMR is a powerful tool to investigate the magnetic ordering at the interface of collinear [7,[27][28][29] and noncollinear ferrimagnets [30,31] as well as spin spirals [32,33]. Recently, a "negative" SMR has been discovered for AFMs [2,[8][9][10], i.e., an SMR with a 90 • phase shift of the angular dependence as compared to FMs, which shows that the AFM Néel vector G tends to align itself normal to the applied magnetic field. The observable in AFMs is therefore the Néel vector rather than the net magnetization [2].…”

“…We assume that the transverse SMR caused by the paramagnetic Dy 3+ moments polarized by the applied field is proportional to m x m y [9,32,58,59]. Adding the contributions of the four Dy sites in the crystallographic unit cell of DFO and the exchange field from the Fe spins acting on the Dy spins as described in the main text, we obtain Eq.…”

“…The magnetization of dielectrics can be detected electrically by the spin Hall magnetoresistance (SMR) in heavy metal contacts with a large spin Hall angle such as Pt [7]. This phenomenon is sensitive to FM but also AFM spin order [2,[8][9][10]. With a Pt contact, information about AFMs can also be retrieved by the spin Seebeck effect (SSE) under a temperature gradient [11][12][13].…”

All‐Electrical Magnon Transport Experiments in Magnetically Ordered Insulators

“…[36,[40][41][42][43][44][121][122][123][124][125][126][127][128][129][130][131][132][133][134][135] In the past years, SMR is prominently used for the investigation of AFIs, which enables us to track the orientation of the Néel order parameter and detect magnetic domains in this class of materials. [124,[131][132][133][134][136][137][138][139][140][141][142][143][144][145] In addition, based on the SMR effect, it is possible to quantify spin-orbit torque effects [36,[146][147][148][149][150][151] and investigate topological spin textures in MOIs. [152][153][154][155][156]…”

Reversible hydrogen control of antiferromagnetic anisotropy in α-Fe2O3

“…Despite all these advantages, they have so far played only an auxiliary role as pinning or exchange bias layers in thin film spintronic devices as their magnetic order is difficult to detect and hard to control 1,15 . Although many recent reports demonstrating clear detection of the AFM-state in insulators by spin-Hall or anisotropic magneto-transport have emerged 7,[16][17][18] , control of the ground-state continues to be a challenge 15 .…”