Evolution of the spin hall magnetoresistance in Cr2O3/Pt bilayers close to the Néel temperature

Schlitz, Richard; Kosub, Tobias; Thomas, Andy; Fabretti, Savio; Nielsch, Kornelius; Makarov, Denys; Goennenwein, Sebastian T. B.

doi:10.1063/1.5019934

Cited by 66 publications

(69 citation statements)

References 29 publications

(45 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…is shown in Figure 3(a-c) for different relative orientations of the magnetic field B and the current j. As a first general observation for all the three cases, we note that the MR monotonously decreases in absolute value when lowering the sample temperature, eventually displaying an almost flat response for T ≤ 40 K. This is a first signature of a magnetic phase transition from the paramagnetic to the antiferromagnetic state in t-Cr 2 O 3 , and a similar behavior can also be observed at the phase transition of Cr 2 O 3 in the corundum structure [11].…”

Section: Magnetoresistance and Hall Effectsupporting

confidence: 69%

Detecting antiferromagnetism in tetragonal Cr2O3 by electrical measurements

et al. 2019

View full text Add to dashboard Cite

The tetragonal phase of chromium (III) oxide, although unstable in the bulk, can be synthesized in epitaxial heterostructures. Theoretical investigation by density functional theory predicts an antiferromagnetic ground state for this compound. We demonstrate experimentally antiferromagnetism up to 40 K in ultrathin films of t-Cr 2 O 3 by electrical measurements exploiting interface effect within a neighboring ultrathin Pt layer. We show that magnetotransport in Pt is affected by both spin-Hall magnetoresistance and magnetic proximity effect while we exclude any role of magnetism for the low-temperature resistance anomaly observed in Pt.

show abstract

Section: Magnetoresistance and Hall Effectsupporting

confidence: 69%

Detecting antiferromagnetism in tetragonal Cr2O3 by electrical measurements

et al. 2019

View full text Add to dashboard Cite

show abstract

“…The SMR in bilayers of antiferromagnets/HM has been investigated only very recently. A positive SMR was claimed for bilayers of SrMnO3/Pt [19] and Cr2O3/W, [20] possibly due to a small canted/uncompensated magnetization M. [21] During the preparation of this work, reports on a positive SMR in paramagnetic Cr2O3/Pt, negative SMR in Cr2O3/Ta [22,23] and a negative SMR in NiO(111)/Pt bilayers, [24,25] where the magnetic field rotates in the NiO(111) easy plane only, in agreement with theoretical predictions [7], were published. during the preparation of this work.…”

Section: Introductionmentioning

confidence: 94%

Full angular dependence of the spin Hall and ordinary magnetoresistance in epitaxial antiferromagnetic NiO(001)/Pt thin films

et al. 2018

View full text Add to dashboard Cite

We report the observation of the three-dimensional angular dependence of the spin Hall magnetoresistance (SMR) in a bilayer of the epitaxial antiferromagnetic insulator NiO(001) and the heavy metal Pt, without any ferromagnetic element. The detected angular-dependent longitudinal and transverse magnetoresistances are measured by rotating the sample in magnetic fields up to 11 T, along three orthogonal planes (xy-, yz-and xz-rotation planes, where the z-axis is orthogonal to the sample plane). The total magnetoresistance has contributions arising from both the SMR and ordinary magnetoresistance. The onset of the SMR signal occurs between 1 and 3 T and no saturation is visible up to 11 T. The three-dimensional angular dependence of the SMR can be explained by a model considering the reversible field-induced redistribution of magnetostrictive antiferromagnetic S-and T-domains in the NiO(001), stemming from the competition between the Zeeman energy and the elastic clamping effect of the non-magnetic MgO substrate. From the observed SMR ratio, we estimate the spin mixing conductance at the NiO/Pt interface to be greater than 2x10 14 Ω -1 m -2 . Our results demonstrate

show abstract

“…The angular dependence additionally disputes long-range antiferromagnetic ordering in our bilayers, since a shift of the extrema by 90 deg compared to the SMR introduced in Eq.1 would be expected for an AFM. [10][11][12]18,24 The existence of a magnetoresistance in PMI/Pt heterostructures has already been reported above the Curie temperature for CoCr 2 O 4 /Pt bilayers with a MR ratio of ∆ρ/ρ 0 < 2 × 10 −6 by Aqeel et al 16 and above the Neel temperature for Cr 2 O 3 /Pt bilayer structures by Schlitz et al 18 with ∆ρ/ρ 0 > 1 × 10 −4 . It has also been reported that no MR was detectable in paramagnetic Gd 3 Ga 5 O 12 (GGG)/Pt heterostructures at room temperature.…”

mentioning

confidence: 92%

“…19 The presence of SMR has been reported by two a) Electronic mail: m.lammel@ifw-dresden.de b) Electronic mail: sebastian.goennenwein@tu-dresden.de groups in different magnetically ordered materials, in the paramagnetic phase above the ordering temperature. 16,18 Since the SMR is primarily studied in the magnetically ordered phase in those works, the authors do not provide a microscopic picture for the SMR in a randomly ordered spin ensemble. Therefore, in this work, we systematically study the SMR in a paramagnetic insulator (PMI)/spin Hall metal bilayer and critically compare the experimental results to the SMR expected from two different microscopic models: one model assumes an ensemble of noninteracting moments, while the other model considers the (induced) net magnetization.…”

mentioning

confidence: 99%

Spin Hall magnetoresistance in heterostructures consisting of noncrystalline paramagnetic YIG and Pt

Lammel

Schlitz

Geishendorf

et al. 2019

Applied Physics Letters

Self Cite

View full text Add to dashboard Cite

The spin Hall magnetoresistance (SMR) effect arises from spin-transfer processes across the interface between a spin Hall active metal and an insulating magnet. While the SMR response of ferrimagnetic and antiferromagnetic insulators has been studied extensively, the SMR of a paramagnetic spin ensemble is not well established. Thus, we investigate herein the magnetoresistive response of as-deposited yttrium iron garnet/platinum thin film bilayers as a function of the orientation and the amplitude of an externally applied magnetic field. Structural and magnetic characterization show no evidence for crystalline order or spontaneous magnetization in the yttrium iron garnet layer. Nevertheless, we observe a clear magnetoresistance response with a dependence on the magnetic field orientation characteristic for the SMR. We propose two models for the origin of the SMR response in paramagnetic insulator/Pt heterostructures. The first model describes the SMR of an ensemble of non-interacting paramagnetic moments, while the second model describes the magnetoresistance arising by considering the total net moment. Interestingly, our experimental data are consistently described by the net moment picture, in contrast to the situation in compensated ferrimagnets or antiferromagnets.Spin Hall magnetoresistance (SMR) 1-3 is commonly observed in ferrimagnetic insulator (FMI)/normal metal (NM) heterostructures when the metal exhibits a large spin-orbit coupling. The SMR arises due to the interplay of the spin-transfer torque, the spin Hall effect (SHE) and the inverse spin Hall effect at the FMI/NM interface. [4][5][6] While the SMR effect is usually discussed in terms of the total (net) magnetization, 1 recent experimental work showed that the SMR does not only probe the net magnetization of FMIs, but is also sensitive to the contributions of the different magnetic sublattices. 7,8 This observation is key to understand the SMR response of more complex magnetic systems, such as canted ferrimagnets 7-9 , antiferromagnets 10-15 , spin spirals 16 or helical phases. 17 To date, SMR measurements have been performed extensively in samples with different long-range (spontaneous) magnetic ordering. 2,7,10,[16][17][18] In contrast, paramagnetic materials have not been in the focus of prior work done for SMR measurements. However, the magnetoresistive response of paramagnetic materials is an interesting topic. For example, magnetoresistance measurements were recently performed in a gated paramagnetic ionic liquid. 19 The presence of SMR has been reported by two groups in different magnetically ordered materials, in the paramagnetic phase above the ordering temperature. 16,18 Since the SMR is primarily studied in the magnetically ordered phase in those works, the authors do not provide a microscopic picture for the SMR in a randomly ordered spin ensemble. Therefore, in this work, we systematically study the SMR in a paramagnetic insulator (PMI)/spin Hall metal bilayer and critically compare the experimental results to the SMR expected from tw...

show abstract

Evolution of the spin hall magnetoresistance in Cr2O3/Pt bilayers close to the Néel temperature

Cited by 66 publications

References 29 publications

Detecting antiferromagnetism in tetragonal Cr2O3 by electrical measurements

Detecting antiferromagnetism in tetragonal Cr2O3 by electrical measurements

Full angular dependence of the spin Hall and ordinary magnetoresistance in epitaxial antiferromagnetic NiO(001)/Pt thin films

Spin Hall magnetoresistance in heterostructures consisting of noncrystalline paramagnetic YIG and Pt

Contact Info

Product

Resources

About