Temperature dependence of the interfacial magnetic anisotropy in W/CoFeB/MgO

The Dzyaloshinskii-Moriya interaction gives rise to a chiral exchange between neighboring spins in the technologically relevant class of perpendicularly magnetized ultrathin film materials. In this paper, we study the temperature dependence of the Dzyaloshinskii-Moriya interaction based on extensive characterization of a thin film which hosts a skyrmion state using both bulk magnetometry and x-ray magnetic circular dichroism photoemission electron microscopy. A version of the Bloch law explicitly for thin film geometries is derived to extract the exchange stiffness. The strength of the Dzyaloshinskii-Moriya interaction, D, is found to have a dependence on the saturation magnetization, M s of D ∝ M 1.86±0.16 s . Further, by extracting the uniaxial anisotropy K u and the exchange stiffness A, we find that D ∝ K 1.02±0.11 u and D ∝ A 0.95±0.07 . Skyrmion radii are also used to extract the strength of the Dzyaloshinskii-Moriya interaction which is compared to that derived from measurements of stripe domains. The origins of the correlations between material parameters are discussed and consequences of these relationships for skyrmion devices are considered.

show abstract

“…1(d). A low T c is consistent with the small room temperature M s of ∼6 × 10 5 A/m at 300 K, which is around half the bulk value [22].…”

Section: Experiments and Resultssupporting

confidence: 72%

Temperature dependence of the Dzyaloshinskii-Moriya interaction in ultrathin films

et al. 2020

View full text Add to dashboard Cite

show abstract

“…As these films are thin enough to support PMA, interfacial strain effects are likely contributing to the temperature dependence of anisotropy and changing its temperature scaling with M s . 39,40 Additionally, given evidence that DMI induces some anisotropy in heavy metal/ferromagnet interfaces, 15 their interrelation may influence the net K u (T).…”

Section: -2mentioning

confidence: 99%

Temperature dependence of the Dzyaloshinskii-Moriya interaction in Pt/Co/Cu thin film heterostructures

Schlotter

Agrawal

Beach

2018

Applied Physics Letters

View full text Add to dashboard Cite

Magnetic materials that exhibit chiral domain walls are of great interest for spintronic devices. In this work, we examine the temperature-dependent behavior of the Dzyaloshinskii-Moriya interaction (DMI) in Pt/Co/Cu thin film heterostructures. We extract the DMI strength, D, from static domain spacing analysis between 300 K and 500 K and compare its temperature dependence to that of the magnetic anisotropy, K u , and saturation magnetization, M s. Consistent with expected scaling in thin films, M s exhibits Bloch-law temperature scaling and K u scales as M s 2:160:1. However, D varies more strongly with temperature than expected, scaling as D / M s 4:960:7 , indicating that interfacial DMI is more sensitive to thermal fluctuations than bulk magnetic properties. We suggest that this may be related to the temperature dependence of locally induced magnetic moments in the Pt underlayer and the 3d-5d orbital interactions at the interface. While we observe stable domain widths in the studied temperature range, a strongly temperature dependent DMI may have significant consequences for potential devices based on the chiral domain wall or skyrmion motion.

show abstract

“…where K 0 is the uniaxial anisotropy constant at zero temperature, M s0 is the spontaneous magnetization of the storage layer at zero temperature. From previous studies, the value of the exponent ξ was experimentally estimated to lie in the range between 2 and 3 [20,[34][35][36][37]. The temperature dependence of the storage layer magnetization is supposed to follow a Bloch law:…”

Section: Modelmentioning

confidence: 99%

“…where T c is the Curie temperature of the storage layer. The exponent "3/2" is slightly different for thin deposited films, and its experimentally determined value equals to 1.73 [34]. Taking into account (3) and (4) and assuming that pulse durations are long enough so that the temperature varies with the voltage as T = T 0 +k V V 2 according to (2), the voltage dependences of the magnetization and anisotropy constant reads:…”

Section: Modelmentioning

confidence: 99%

Impact of Joule heating on the stability phase diagrams of perpendicular magnetic tunnel junctions

et al. 2018

View full text Add to dashboard Cite

Measured switching voltage-field (V-H) diagrams of perpendicular magnetic tunnel junctions (pMTJ) exhibit unexpected behavior at high voltages associated with significant heating of the storage layer. The boundaries deviate from the critical lines corresponding to the coercive field, which contrasts with the theoretically predicted behavior of a standard macrospin-based model. Combining recent experimental studies of the temperature dependence of spin polarization and perpendicular magnetic anisotropy (PMA) we are proposing a modified model. Our approach takes into account the Joule heating during the writing pulse, which reduces the spin polarization and the anisotropy, thereby reducing the spin torque efficiency and the coercive field during the switching. The numerical macrospin simulations based on this model are in agreement with our experimental measurements and consistent with the results derived from the linearization of Landau-Lifshitz-Gilbert equation.

show abstract

Temperature dependence of the interfacial magnetic anisotropy in W/CoFeB/MgO

Cited by 69 publications

References 25 publications

Temperature dependence of the Dzyaloshinskii-Moriya interaction in ultrathin films

Temperature dependence of the Dzyaloshinskii-Moriya interaction in ultrathin films

Temperature dependence of the Dzyaloshinskii-Moriya interaction in Pt/Co/Cu thin film heterostructures

Impact of Joule heating on the stability phase diagrams of perpendicular magnetic tunnel junctions

Contact Info

Product

Resources

About