Structural, electronic, and magnetic investigation of magnetic ordering in MBE-grown CrxSb2−xTe3 thin films

Journal article

We report the structural, electronic, and magnetic study of Cr-doped Sb2Te3 thin films grown by a two-step deposition process using molecular-beam epitaxy (MBE). The samples were investigated using a variety of complementary techniques, namely, x-ray diffraction (XRD), atomic force microscopy, SQUID magnetometry, magneto-transport, and polarized neutron reflectometry (PNR). It is found that the samples retain good crystalline order up to a doping level of x = 0:42 (in CrxSb2 xTe3), above which degradation of the crystal structure is observed by XRD. Fits to the recorded XRD spectra indicate a general reduction in c-axis lattice parameter as a function of doping, consistent with substitutional doping with an ion of smaller ionic radius. The samples show soft ferromagnetic behavior with the easy axis of magnetization being out-of-plane. The saturation magnetization is dependent on the doping level, and reaches from ~2 μB to almost 3 μB per Cr ion. The transition temperature (Tc) depends strongly on the Cr concentration and is found to increase with doping concentration. For the highest achievable doping level for phase-pure films of x = 0:42, a Tc of 125 K was determined. Electric transport measurements find surface-dominated transport below ~10 K. The magnetic properties extracted from anomalous Hall effect data are in excellent agreement with the magnetometry data. PNR studies indicate a uniform magnetization profile throughout the film, with no indication of enhanced magnetic order towards the sample surface.

Authors: Collins-McIntyre, L; Duffy, L; Singh, A; Steinke, N; Kinane, C

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: European Physical Society
• Journal: Europhysics Letters
• Publication date: 2016-08-01
• Acceptance date: 2016-08-02
• DOI: 10.1209/0295-5075/115/27006
• ISSN: 1286-4854
• Keywords: Magnetic semiconductors; Insulators; Magnetic impurity interaction