Dzyaloshinskii–Moriya interaction (DMI) induced ferromagnetic (FM) skyrmions in chiral magnets have been reported last decade1,2. On the other hand, chiral antiferromagnet could be a great candidate to host antiferromagnetic (AFM) skyrmions, which have not been studied yet. The emergence of room-temperature FM skyrmions has been reported in the field β-Mn type Fe2-xPdxMo3N epitaxial thin films1. We report Pd doping effect on magnetic and transport properties of a series of chiral antiferromagnetic filled β-Mn type Co2-xPdxMo3N (CPMN) thin films.
A series of CPMN (x = 0 ~ 1.61) thin films were fabricated on c-plane sapphire substrates. Figure 1(a) shows the 2θ/θ scan XRD pattern of a CPMN thin film with x = 1.01, indicating that CPMN films grown epitaxially in the (110) direction, as in case of Fe2-xPdxMo3N/Al2O31. Figure 1(b) shows the x dependence of c0 indicating the on-site doping of Pd. Figure 1(c) shows the M-T curve of a CPMN film with x = 1.01, where two anomalies are identified, which appeared in all CPMN films. The high-temperature anomaly could be related to the Néel temperature TN, as in case of bulk Co2Mo3N3. The magnetization MS at 200 K is 3×10-2 μB/f.u., which is 70 times smaller than that of ferromagnetic Fe2-xPdxMo3N films1, which suggests that the high-temperature magnetic phase is a canted antiferromagnetic (AFM) phase. The low-temperature anomaly can be ascribed to the spin reorientation, at which temperature (TSR) the transition between AFM phase and spiral phase occurs as reported in chiral antiferromagnetic K2V3O84. The low-temperature spiral phase is also revealed by topological Hall effect (THE) at 4 K (Fig. 1(d)). The vanishing THE in canted AFM phase at 200 K (Fig. 1(d)) might be due to the AFM skyrmions. We will report the details of magnetic and transport properties of CPMN system.
References 1 B. W. Qiang et al., Appl. Phys. Lett. 117, 142401 (2020). 2 R. Saha et al., Nat. Commun. 10, 5305 (2019). 3 W. Li et al. Phys. Rev. B 93, 060409(R) (2016). 4 M. D. Lumsden et al., Phys. Rev. Lett. 86, 159 (2001)