Single Crystal Growth and Spin Polarization Measurements of Diluted Magnetic Semiconductor (BaK)(ZnMn)2As2

Abstract

Recently a new diluted magnetic semiconductor, (Ba,K)(Zn,Mn)2As2 (BZA), with high Curie temperature was discovered, showing an independent spin and charge-doping mechanism. This makes BZA a promising material for spintronics devices. We report the successful growth of a BZA single crystal for the first time in this study. An Andreev reflection junction, which can be used to evaluate spin polarization, was fabricated based on the BZA single crystal. A 66% spin polarization of the BZA single crystal was obtained by Andreev reflection spectroscopy analysis.

Asperomagnetic order in diluted magnetic semiconductor (Ba,Na)(Zn,Mn)2As2

“…In contrast, v FC continues to increase with decreasing temperature for both field orientations. Similar bifurcation behavior of v ZFC and v FC has also been observed in BKZMA single crystals 14 as well as in polycrystalline BKZMA and Ba(Zn 1-2x Mn x Cu x ) 2 As 2 samples. 12,15 The ac susceptibility of the BNZMA sample has also been measured at various frequencies to probe the origin of the bifurcation behavior.…”

“…ð Þ=R xx 0 ð Þ, remains negative up to the highest magnetic field (9 T) and exhibits no signature of saturation. The magnitude of MR increases with decreasing temperature and reaches about 26% at B ¼ 9 T and T ¼ 2 K. Similar negative MRs have been observed in other magnetic semiconductors, such as (Eu,Gd)Se 21 and BKZMA, 14 can be attributed to reduced spindependent scatterings in higher magnetic fields.…”

“…36 The obtained inelastic scattering parameters C ¼ 0.6-0.75 meV are large but still less than the superconducting gap, supporting the reliability of the extracted P. Interestingly, the average spin polarization is not much lower than P ¼ 66% obtained for the BKZMA single crystals using the same technique. 14 The coexistence of the partial spin polarization, the positive Curie-Weiss temperature, and the spin-glass-like behavior in susceptibility suggests a complex spin structure in the ground state of BNZMA. The substantial spin polarization and the positive Curie-Weiss temperature (albeit not very large) indicate that the FM interactions are stronger than the AFM counterparts at an overall level.…”

“…In both polycrystalline and single-crystalline samples, the zero-fieldcooled (ZFC) magnetization was found deviating strongly from the field-cooled (FC) magnetization below a certain temperature. 12,14 In Ref. 12, such a deviation is attributed to strong magnetic anisotropy in BKZMA (evidenced by coercive fields up to l 0 H c $ 1 T).…”

Tailoring magnetism in semiconductors

“…Despite these advances, the prior BZA research posed an important constraint: all the samples formed as a powder were polycrystalline, preventing many exciting developments in which BZA could be a parts of high-quality heterostructures that combine materials of very diverse properties [6]. In this context, the latest work of Zhao et al [11] demonstrates an important breakthrough; not only does it realize the first single crystal BZA, but through a fabri-cation of superconductor/BZA heterostructure extracts the degree of carrier spin polarization, one of the key figure of merit for DMS and other magnets [3]. Probing this spin polarization was made possible by the process of Andreev reflection through conductance measurements.…”