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Perpendicularly magnetized Co-based Heusler alloys are promising candidates in high-performance spintronic devices. However, there is a contradiction between thermal stability and damping-like spin–orbit torque (SOT) efficiency in Co-based Heusler alloys with interface-induced perpendicular magnetic anisotropy (PMA). Here, we present epitaxially grown perpendicularly magnetized Mn1+xCo2−xAl (MCA) Heusler alloys through tetragonal distortion. Ferrimagnetism and distortion-induced PMA are obtained in MCA Heusler alloys. A large effective spin Hall angle (θeff) up to 0.33 is experimentally demonstrated in Pt/MCA bilayers, markedly surpassing that in conventional Pt/FM bilayers. Consequently, SOT-induced efficient magnetization switching is realized in Pt/MCA bilayers, with a critical switching current density (Jc) as low as 4 × 107 A/cm2. The large θeff and high SOT efficiency would be attributed to the staggered magnetic exchange torques in the ferrimagnetic MCA Heusler alloys. These findings demonstrate that perpendicularly magnetized ferrimagnetic MCA Heusler alloys are highly promising for high-density SOT-magnetic random-access memory with superior thermal stability and low power consumption. [ABSTRACT FROM AUTHOR]

The indirect interlayer exchange coupling (IEC) between two magnetic layers holds significant importance in the field of spintronics and has been widely used in the construction of synthetic antiferromagnets. Recently, the interlayer Dzyaloshinskii–Moriya interaction (DMI), antisymmetric counterpart of IEC, has been discovered in magnetic trilayers with a heavy-metal spacer. In this study, we present an investigation on antisymmetric and symmetric counterparts of IEC in D022-Mn3Ga/Pt/Co trilayers with orthogonal magnetization. Due to the strong interlayer DMI across the entire multilayer, the symmetry of magnetic reversal process was broken, leading to an enhanced chiral exchange-bias field of 42.7 Oe in the Co layer. In addition, field-free spin–orbit torque (SOT) switching of D022-Mn3Ga layer has been realized in Hall bar devices. In-plane field dependence analysis of the SOT switching behavior reveals that the symmetric counterpart of IEC exhibits antiferromagnetic characteristics within the spacer thickness range of 2 nm ≤ tPt ≤5 nm. Moreover, the magnitude of both antisymmetric and symmetric counterparts of IEC exhibits an exponential decreasing trend with increasing tPt. These findings hold significant implications for the design and manipulation of three-dimensional chiral spin textures in the future spintronic devices. [ABSTRACT FROM AUTHOR]

Rare-earth-free perpendicularly magnetized L10-MnxAl alloy holds promise for low-cost permanent magnets and high-performance spintronic devices. In this Letter, we report a large-scale modulation of perpendicular magnetic anisotropy (PMA) in MnxAl films by changing the composition x. Through utilizing a lattice-matching B2-CoGa underlayer and optimizing growth conditions, the 30-nm-thick MnxAl films can maintain excellent PMA in a wide composition range (0.7 ≤ x ≤ 3). Meanwhile, the crystalline structure and magnetic properties exhibit a strong dependence on the composition with saturation magnetization changing from 443.75 to 20.52 kA/m, coercivity from 0.22 to 5.38 T, and PMA constant up to 1.34 × 106 J/m3. Combining experimental and calculation results, we confirm the existence of ferrimagnetic-like state in MnxAl under Mn-rich conditions. Further experiments validate the continued efficacy of our method in ultrathin MnxAl films, and spin–orbit torque induced magnetization switching has been realized. These results offer valuable insights into the modulation of fundamental properties and promote the potential application of MnxAl alloy. [ABSTRACT FROM AUTHOR]

Artificial ferrimagnetic [D022-Mn3Ga/Co2MnSi]N superlattices ([Mn3Ga/CMS]N SLs) combining perpendicular magnetic anisotropy as well as exceptional thermal and magnetic stability hold promises in functional spintronic devices. However, the relevant precession dynamics are still lacking. Here, we report on the magnetic dynamic properties in [Mn3Ga/CMS]5 SLs investigated by the time-resolved magneto-optical Kerr effect (TRMOKE) measurements. The magnetization precession process and magnetic damping constant (α0) of [Mn3Ga/CMS]5 SLs rely heavily on the thickness of Mn3Ga layer (tMn3Ga). In addition, α0 is found to be higher with increasing tMn3Ga, but is not simply scaled by the uniaxial magnetic anisotropy (Ku), which can be ascribed to the contribution of spin–orbit interaction combined with the additional contributions, like spin-pumping. Furthermore, a large Ku value of 1.33 Merg/cm3 and a low α0 of 0.022 have been simultaneously obtained in [Mn3Ga/CMS]5 SL with tMn3Ga = 1.5 nm. This study contributes to the design of high-performance spintronic devices based on [Mn3Ga/CMS]N SLs. [ABSTRACT FROM AUTHOR]

Perpendicularly magnetized ferrimagnets have shown potential application in nonvolatile, high-density, and ultrafast spintronic devices. Achieving this requires tuning the material performance of ultrathin ferrimagnetic films. Here, we present an experimental demonstration of tunable perpendicular magnetic anisotropy (PMA) and spin–orbit torque (SOT) switching behavior in a ferrimagnetic Heusler alloy D022-Mn3Ga based multilayers by introducing lattice-matching underlayers. It is found that the highly (001) orientated crystalline structure is well maintained, whereas coercivity, anisotropy field, and PMA constant rely heavily on the specific underlayer. Owing to the strong out-of-plane exchange coupling, the PMA constant of Co2MnSi/D022-Mn3Ga is significantly enhanced by four times and reaches 12.1 Merg/cm3. Moreover, the SOT measurements suggest that Fe/D022-Mn3Ga and Co2MnSi/D022-Mn3Ga exhibit analog and abrupt switching dynamics, respectively. This contrasting SOT switching behavior is attributed to different magnetization switching mechanisms, verified by the direct imaging of the nanoscale magnetic domain. These results provide a deep insight into the manipulation of not only fundamental magnetic properties but also SOT switching of ferrimagnetic Heusler alloys. [ABSTRACT FROM AUTHOR]

Manipulating magnetization via power-efficient spin-orbit torque (SOT) has garnered significant attention in the field of spin-based memory and logic devices. However, the damping-like SOT efficiency (ξ DL ) in heavy metal (HM)/ferromagnetic metal (FM) bilayers is relatively small due to the strong spin dephasing accompanied by additional spin polarization decay. Furthermore, the perpendicular magnetic anisotropy (PMA) originating from the HM/FM interface is constrained by the thickness of FM, which is unfavorable for thermal stability in practical applications. Consequently, it is valuable to develop systems that not only exhibit large ξ DL but also balance thermal stability. In this work, we designed antiferromagnetic-coupled [Co/Gd] N multilayers, where staggered Co and Gd magnetic moments effectively suppress the spin dephasing and additional spin polarization decay. The ordered Co-Gd arrangements along the out-of-plane direction provide bulk PMA, endowing Pt/[Co/Gd] N high thermal stability. The SOT of Pt/[Co/Gd] N was systematically studied with N, demonstrating a significantly large ξ DL of up to 0.66. The ξ DL of Pt/[Co/Gd] N is greater than those of Pt/Co and Pt/ferrimagnetic alloys. This significant enhancement relies on the effective suppression of spin dephasing in [Co/Gd] N . Our work highlights that the antiferromagnetic-coupled [Co/Gd] N multilayer is a promising candidate for low-consumption and high-density spintronic devices.