Long-distance magnon transport in the van der Waals antiferromagnet CrPS4

Abstract

We demonstrate the potential of van der Waals magnets for spintronic applications by reporting long-distance magnon spin transport in the electrically insulating antiferromagnet chromium thiophosphate (CrPS 4 ) with perpendicular magnetic anisotropy. We inject and detect magnon spins nonlocally by Pt contacts and monitor the nonlocal resistance as a function of an in-plane magnetic field up to 7 T. We observe a nonlocal resistance over distances up to at least a micron below the Néel temperature (T N = 38 K) close to magnetic field strengths that saturate the sublattice magnetizations.

Soft magnons in anisotropic ferromagnets

“…We predict enhanced nonlocal magnon transport caused by the divergence of the magnon spin for magnets with a magnetic field applied perpendicular to a uniaxial magnetic anisotropy, which is stronger in two than in three dimensions. The effect should contribute to the observation of magnon transport above and down to the spin-flip transition at which the spin sublattices are forced to align ferromagnetically [17] and we expect enhanced nonlocal signals carried by the soft acoustic magnon as in case C. However, more work is necessary to fully understand the experiments [19].…”

“…De Wal et al [17] studied nonlocal magnon transport in an antiferromagnetic van der Waals film with a perpendicular Néel vector. An in-plane magnetic field cants the two sublattices until the material becomes ferrimagnetically ordered at the spin-flip transition, not unlike the in-plane spin texture of hematite at high fields.…”

Highly Anisotropic Mechanical Response of the Van der Waals Magnet CrPS4

“…In fact, these anisotropic properties are often coupled, offering a fruitful avenue for the control of collective excitations, such as excitons, phonons, or magnons, and allowing the design of new devices in fields such as magnonics, spintronics, optoelectronics, or information storage and processing. [4,5] In this regard, van der Waals magnets with in-plane anisotropy offer unique opportunities, both in the fundamental understanding of these materials and in terms of applications, as recently shown by the exciton-magnon coupling reported for CrSBr or the fabrication of spintronic and magnonic devices based on 2D magnets, [6][7][8][9][10] among others. A promising van der Waals magnet exhibiting an interplay between the optical, electrical, magnetic, and structural properties is the magnetic van der Waals semiconductor CrPS 4 .…”

“…[12][13][14]18] CrPS 4 can be thinned down to the single layer limit while preserving its magnetic ordering, [19] and thin-layers have been incorporated into electronic devices, showing magnetic states controllable by the gate voltage. [20] In addition, the insulating nature of CrPS 4 at low temperatures is ideal for the electrical excitation and detection of magnons, [6] and the fabrication of multi-bit read-only memories. [21] Despite the exciting properties of CrPS 4 described above, the role of the underlying in-plane anisotropic structural behavior remains still unexplored.…”

Towards molecular controlled magnonics

“…2–4 In this context, the recent emergence of van der Waals (vdW) magnetic materials that retain long-range magnetic order down to the 2D limit, such as the layered antiferromagnets CrI 3 or CrSBr, 5,6 provides unprecedented opportunities for spintronics and magnonics. 7 In this class of materials, the magnetic properties can be tuned by electric fields, 8 electrostatic doping, 9 strain engineering 10 or light 11 and can hold long-lived spin waves (SWs) in the GHz to THz range, 12,13 thus opening new horizons for information and quantum technologies. Magnonics is a rapidly growing research field that investigates the transmission, storage, and processing of information by using SWs, 14 whose quanta are called magnons.…”